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9 | 2439-2442 | C J Davisson and L H |
9 | 2440-2443 | J Davisson and L H Germer later
experimentally verified the wave nature of electrons in 1927 |
9 | 2441-2444 | Davisson and L H Germer later
experimentally verified the wave nature of electrons in 1927 Louis de Broglie argued that the electron in its circular orbit,
as proposed by Bohr, must be seen as a particle wave |
9 | 2442-2445 | H Germer later
experimentally verified the wave nature of electrons in 1927 Louis de Broglie argued that the electron in its circular orbit,
as proposed by Bohr, must be seen as a particle wave In
analogy to waves travelling on a string, particle waves too
can lead to standing waves under resonant conditions |
9 | 2443-2446 | Germer later
experimentally verified the wave nature of electrons in 1927 Louis de Broglie argued that the electron in its circular orbit,
as proposed by Bohr, must be seen as a particle wave In
analogy to waves travelling on a string, particle waves too
can lead to standing waves under resonant conditions From
Chapter 14 of Class XI Physics textbook, we know that when
a string is plucked, a vast number of wavelengths are excited |
9 | 2444-2447 | Louis de Broglie argued that the electron in its circular orbit,
as proposed by Bohr, must be seen as a particle wave In
analogy to waves travelling on a string, particle waves too
can lead to standing waves under resonant conditions From
Chapter 14 of Class XI Physics textbook, we know that when
a string is plucked, a vast number of wavelengths are excited However only those wavelengths survive which have nodes
at the ends and form the standing wave in the string |
9 | 2445-2448 | In
analogy to waves travelling on a string, particle waves too
can lead to standing waves under resonant conditions From
Chapter 14 of Class XI Physics textbook, we know that when
a string is plucked, a vast number of wavelengths are excited However only those wavelengths survive which have nodes
at the ends and form the standing wave in the string It means
that in a string, standing waves are formed when the total distance
travelled by a wave down the string and back is one wavelength, two
wavelengths, or any integral number of wavelengths |
9 | 2446-2449 | From
Chapter 14 of Class XI Physics textbook, we know that when
a string is plucked, a vast number of wavelengths are excited However only those wavelengths survive which have nodes
at the ends and form the standing wave in the string It means
that in a string, standing waves are formed when the total distance
travelled by a wave down the string and back is one wavelength, two
wavelengths, or any integral number of wavelengths Waves with other
wavelengths interfere with themselves upon reflection and their
amplitudes quickly drop to zero |
9 | 2447-2450 | However only those wavelengths survive which have nodes
at the ends and form the standing wave in the string It means
that in a string, standing waves are formed when the total distance
travelled by a wave down the string and back is one wavelength, two
wavelengths, or any integral number of wavelengths Waves with other
wavelengths interfere with themselves upon reflection and their
amplitudes quickly drop to zero For an electron moving in nth circular
orbit of radius rn, the total distance is the circumference of the orbit,
2prn |
9 | 2448-2451 | It means
that in a string, standing waves are formed when the total distance
travelled by a wave down the string and back is one wavelength, two
wavelengths, or any integral number of wavelengths Waves with other
wavelengths interfere with themselves upon reflection and their
amplitudes quickly drop to zero For an electron moving in nth circular
orbit of radius rn, the total distance is the circumference of the orbit,
2prn Thus
FIGURE 12 |
9 | 2449-2452 | Waves with other
wavelengths interfere with themselves upon reflection and their
amplitudes quickly drop to zero For an electron moving in nth circular
orbit of radius rn, the total distance is the circumference of the orbit,
2prn Thus
FIGURE 12 8 A standing wave
is shown on a circular orbit
where four de Broglie
wavelengths fit into the
circumference of the orbit |
9 | 2450-2453 | For an electron moving in nth circular
orbit of radius rn, the total distance is the circumference of the orbit,
2prn Thus
FIGURE 12 8 A standing wave
is shown on a circular orbit
where four de Broglie
wavelengths fit into the
circumference of the orbit Rationalised 2023-24
Physics
302
2p rn = nl, n = 1, 2, 3 |
9 | 2451-2454 | Thus
FIGURE 12 8 A standing wave
is shown on a circular orbit
where four de Broglie
wavelengths fit into the
circumference of the orbit Rationalised 2023-24
Physics
302
2p rn = nl, n = 1, 2, 3 (12 |
9 | 2452-2455 | 8 A standing wave
is shown on a circular orbit
where four de Broglie
wavelengths fit into the
circumference of the orbit Rationalised 2023-24
Physics
302
2p rn = nl, n = 1, 2, 3 (12 12)
Figure 12 |
9 | 2453-2456 | Rationalised 2023-24
Physics
302
2p rn = nl, n = 1, 2, 3 (12 12)
Figure 12 8 illustrates a standing particle wave on a circular orbit
for n = 4, i |
9 | 2454-2457 | (12 12)
Figure 12 8 illustrates a standing particle wave on a circular orbit
for n = 4, i e |
9 | 2455-2458 | 12)
Figure 12 8 illustrates a standing particle wave on a circular orbit
for n = 4, i e , 2prn = 4l, where l is the de Broglie wavelength of the electron
moving in nth orbit |
9 | 2456-2459 | 8 illustrates a standing particle wave on a circular orbit
for n = 4, i e , 2prn = 4l, where l is the de Broglie wavelength of the electron
moving in nth orbit From Chapter 11, we have l = h/p, where p is the
magnitude of the electron’s momentum |
9 | 2457-2460 | e , 2prn = 4l, where l is the de Broglie wavelength of the electron
moving in nth orbit From Chapter 11, we have l = h/p, where p is the
magnitude of the electron’s momentum If the speed of the electron is
much less than the speed of light, the momentum is mvn |
9 | 2458-2461 | , 2prn = 4l, where l is the de Broglie wavelength of the electron
moving in nth orbit From Chapter 11, we have l = h/p, where p is the
magnitude of the electron’s momentum If the speed of the electron is
much less than the speed of light, the momentum is mvn Thus, l = h/
mvn |
9 | 2459-2462 | From Chapter 11, we have l = h/p, where p is the
magnitude of the electron’s momentum If the speed of the electron is
much less than the speed of light, the momentum is mvn Thus, l = h/
mvn From Eq |
9 | 2460-2463 | If the speed of the electron is
much less than the speed of light, the momentum is mvn Thus, l = h/
mvn From Eq (12 |
9 | 2461-2464 | Thus, l = h/
mvn From Eq (12 12), we have
2p rn = n h/mvn or m vn rn = nh/2p
This is the quantum condition proposed by Bohr for the angular
momentum of the electron [Eq |
9 | 2462-2465 | From Eq (12 12), we have
2p rn = n h/mvn or m vn rn = nh/2p
This is the quantum condition proposed by Bohr for the angular
momentum of the electron [Eq (12 |
9 | 2463-2466 | (12 12), we have
2p rn = n h/mvn or m vn rn = nh/2p
This is the quantum condition proposed by Bohr for the angular
momentum of the electron [Eq (12 15)] |
9 | 2464-2467 | 12), we have
2p rn = n h/mvn or m vn rn = nh/2p
This is the quantum condition proposed by Bohr for the angular
momentum of the electron [Eq (12 15)] In Section 12 |
9 | 2465-2468 | (12 15)] In Section 12 5, we saw that
this equation is the basis of explaining the discrete orbits and energy
levels in hydrogen atom |
9 | 2466-2469 | 15)] In Section 12 5, we saw that
this equation is the basis of explaining the discrete orbits and energy
levels in hydrogen atom Thus de Broglie hypothesis provided an
explanation for Bohr’s second postulate for the quantisation of angular
momentum of the orbiting electron |
9 | 2467-2470 | In Section 12 5, we saw that
this equation is the basis of explaining the discrete orbits and energy
levels in hydrogen atom Thus de Broglie hypothesis provided an
explanation for Bohr’s second postulate for the quantisation of angular
momentum of the orbiting electron The quantised electron orbits and
energy states are due to the wave nature of the electron and only resonant
standing waves can persist |
9 | 2468-2471 | 5, we saw that
this equation is the basis of explaining the discrete orbits and energy
levels in hydrogen atom Thus de Broglie hypothesis provided an
explanation for Bohr’s second postulate for the quantisation of angular
momentum of the orbiting electron The quantised electron orbits and
energy states are due to the wave nature of the electron and only resonant
standing waves can persist Bohr’s model, involving classical trajectory picture (planet-like electron
orbiting the nucleus), correctly predicts the gross features of the
hydrogenic atoms*, in particular, the frequencies of the radiation emitted
or selectively absorbed |
9 | 2469-2472 | Thus de Broglie hypothesis provided an
explanation for Bohr’s second postulate for the quantisation of angular
momentum of the orbiting electron The quantised electron orbits and
energy states are due to the wave nature of the electron and only resonant
standing waves can persist Bohr’s model, involving classical trajectory picture (planet-like electron
orbiting the nucleus), correctly predicts the gross features of the
hydrogenic atoms*, in particular, the frequencies of the radiation emitted
or selectively absorbed This model however has many limitations |
9 | 2470-2473 | The quantised electron orbits and
energy states are due to the wave nature of the electron and only resonant
standing waves can persist Bohr’s model, involving classical trajectory picture (planet-like electron
orbiting the nucleus), correctly predicts the gross features of the
hydrogenic atoms*, in particular, the frequencies of the radiation emitted
or selectively absorbed This model however has many limitations Some are:
(i)
The Bohr model is applicable to hydrogenic atoms |
9 | 2471-2474 | Bohr’s model, involving classical trajectory picture (planet-like electron
orbiting the nucleus), correctly predicts the gross features of the
hydrogenic atoms*, in particular, the frequencies of the radiation emitted
or selectively absorbed This model however has many limitations Some are:
(i)
The Bohr model is applicable to hydrogenic atoms It cannot be
extended even to mere two electron atoms such as helium |
9 | 2472-2475 | This model however has many limitations Some are:
(i)
The Bohr model is applicable to hydrogenic atoms It cannot be
extended even to mere two electron atoms such as helium The analysis
of atoms with more than one electron was attempted on the lines of
Bohr’s model for hydrogenic atoms but did not meet with any success |
9 | 2473-2476 | Some are:
(i)
The Bohr model is applicable to hydrogenic atoms It cannot be
extended even to mere two electron atoms such as helium The analysis
of atoms with more than one electron was attempted on the lines of
Bohr’s model for hydrogenic atoms but did not meet with any success Difficulty lies in the fact that each electron interacts not only with the
positively charged nucleus but also with all other electrons |
9 | 2474-2477 | It cannot be
extended even to mere two electron atoms such as helium The analysis
of atoms with more than one electron was attempted on the lines of
Bohr’s model for hydrogenic atoms but did not meet with any success Difficulty lies in the fact that each electron interacts not only with the
positively charged nucleus but also with all other electrons The formulation of Bohr model involves electrical force between
positively charged nucleus and electron |
9 | 2475-2478 | The analysis
of atoms with more than one electron was attempted on the lines of
Bohr’s model for hydrogenic atoms but did not meet with any success Difficulty lies in the fact that each electron interacts not only with the
positively charged nucleus but also with all other electrons The formulation of Bohr model involves electrical force between
positively charged nucleus and electron It does not include the
electrical forces between electrons which necessarily appear in
multi-electron atoms |
9 | 2476-2479 | Difficulty lies in the fact that each electron interacts not only with the
positively charged nucleus but also with all other electrons The formulation of Bohr model involves electrical force between
positively charged nucleus and electron It does not include the
electrical forces between electrons which necessarily appear in
multi-electron atoms (ii) While the Bohr’s model correctly predicts the frequencies of the light
emitted by hydrogenic atoms, the model is unable to explain the
relative intensities of the frequencies in the spectrum |
9 | 2477-2480 | The formulation of Bohr model involves electrical force between
positively charged nucleus and electron It does not include the
electrical forces between electrons which necessarily appear in
multi-electron atoms (ii) While the Bohr’s model correctly predicts the frequencies of the light
emitted by hydrogenic atoms, the model is unable to explain the
relative intensities of the frequencies in the spectrum In emission
spectrum of hydrogen, some of the visible frequencies have weak
intensity, others strong |
9 | 2478-2481 | It does not include the
electrical forces between electrons which necessarily appear in
multi-electron atoms (ii) While the Bohr’s model correctly predicts the frequencies of the light
emitted by hydrogenic atoms, the model is unable to explain the
relative intensities of the frequencies in the spectrum In emission
spectrum of hydrogen, some of the visible frequencies have weak
intensity, others strong Why |
9 | 2479-2482 | (ii) While the Bohr’s model correctly predicts the frequencies of the light
emitted by hydrogenic atoms, the model is unable to explain the
relative intensities of the frequencies in the spectrum In emission
spectrum of hydrogen, some of the visible frequencies have weak
intensity, others strong Why Experimental observations depict that
some transitions are more favoured than others |
9 | 2480-2483 | In emission
spectrum of hydrogen, some of the visible frequencies have weak
intensity, others strong Why Experimental observations depict that
some transitions are more favoured than others Bohr’s model is
unable to account for the intensity variations |
9 | 2481-2484 | Why Experimental observations depict that
some transitions are more favoured than others Bohr’s model is
unable to account for the intensity variations Bohr’s model presents an elegant picture of an atom and cannot be
generalised to complex atoms |
9 | 2482-2485 | Experimental observations depict that
some transitions are more favoured than others Bohr’s model is
unable to account for the intensity variations Bohr’s model presents an elegant picture of an atom and cannot be
generalised to complex atoms For complex atoms we have to use a new
and radical theory based on Quantum Mechanics, which provides a more
complete picture of the atomic structure |
9 | 2483-2486 | Bohr’s model is
unable to account for the intensity variations Bohr’s model presents an elegant picture of an atom and cannot be
generalised to complex atoms For complex atoms we have to use a new
and radical theory based on Quantum Mechanics, which provides a more
complete picture of the atomic structure *
Hydrogenic atoms are the atoms consisting of a nucleus with positive charge
+Ze and a single electron, where Z is the proton number |
9 | 2484-2487 | Bohr’s model presents an elegant picture of an atom and cannot be
generalised to complex atoms For complex atoms we have to use a new
and radical theory based on Quantum Mechanics, which provides a more
complete picture of the atomic structure *
Hydrogenic atoms are the atoms consisting of a nucleus with positive charge
+Ze and a single electron, where Z is the proton number Examples are hydrogen
atom, singly ionised helium, doubly ionised lithium, and so forth |
9 | 2485-2488 | For complex atoms we have to use a new
and radical theory based on Quantum Mechanics, which provides a more
complete picture of the atomic structure *
Hydrogenic atoms are the atoms consisting of a nucleus with positive charge
+Ze and a single electron, where Z is the proton number Examples are hydrogen
atom, singly ionised helium, doubly ionised lithium, and so forth In these
atoms more complex electron-electron interactions are nonexistent |
9 | 2486-2489 | *
Hydrogenic atoms are the atoms consisting of a nucleus with positive charge
+Ze and a single electron, where Z is the proton number Examples are hydrogen
atom, singly ionised helium, doubly ionised lithium, and so forth In these
atoms more complex electron-electron interactions are nonexistent Rationalised 2023-24
303
Atoms
SUMMARY
1 |
9 | 2487-2490 | Examples are hydrogen
atom, singly ionised helium, doubly ionised lithium, and so forth In these
atoms more complex electron-electron interactions are nonexistent Rationalised 2023-24
303
Atoms
SUMMARY
1 Atom, as a whole, is electrically neutral and therefore contains equal
amount of positive and negative charges |
9 | 2488-2491 | In these
atoms more complex electron-electron interactions are nonexistent Rationalised 2023-24
303
Atoms
SUMMARY
1 Atom, as a whole, is electrically neutral and therefore contains equal
amount of positive and negative charges 2 |
9 | 2489-2492 | Rationalised 2023-24
303
Atoms
SUMMARY
1 Atom, as a whole, is electrically neutral and therefore contains equal
amount of positive and negative charges 2 In Thomson’s model, an atom is a spherical cloud of positive charges
with electrons embedded in it |
9 | 2490-2493 | Atom, as a whole, is electrically neutral and therefore contains equal
amount of positive and negative charges 2 In Thomson’s model, an atom is a spherical cloud of positive charges
with electrons embedded in it 3 |
9 | 2491-2494 | 2 In Thomson’s model, an atom is a spherical cloud of positive charges
with electrons embedded in it 3 In Rutherford’s model, most of the mass of the atom and all its positive
charge are concentrated in a tiny nucleus (typically one by ten thousand
the size of an atom), and the electrons revolve around it |
9 | 2492-2495 | In Thomson’s model, an atom is a spherical cloud of positive charges
with electrons embedded in it 3 In Rutherford’s model, most of the mass of the atom and all its positive
charge are concentrated in a tiny nucleus (typically one by ten thousand
the size of an atom), and the electrons revolve around it 4 |
9 | 2493-2496 | 3 In Rutherford’s model, most of the mass of the atom and all its positive
charge are concentrated in a tiny nucleus (typically one by ten thousand
the size of an atom), and the electrons revolve around it 4 Rutherford nuclear model has two main difficulties in explaining the
structure of atom: (a) It predicts that atoms are unstable because the
accelerated electrons revolving around the nucleus must spiral into
the nucleus |
9 | 2494-2497 | In Rutherford’s model, most of the mass of the atom and all its positive
charge are concentrated in a tiny nucleus (typically one by ten thousand
the size of an atom), and the electrons revolve around it 4 Rutherford nuclear model has two main difficulties in explaining the
structure of atom: (a) It predicts that atoms are unstable because the
accelerated electrons revolving around the nucleus must spiral into
the nucleus This contradicts the stability of matter |
9 | 2495-2498 | 4 Rutherford nuclear model has two main difficulties in explaining the
structure of atom: (a) It predicts that atoms are unstable because the
accelerated electrons revolving around the nucleus must spiral into
the nucleus This contradicts the stability of matter (b) It cannot
explain the characteristic line spectra of atoms of different elements |
9 | 2496-2499 | Rutherford nuclear model has two main difficulties in explaining the
structure of atom: (a) It predicts that atoms are unstable because the
accelerated electrons revolving around the nucleus must spiral into
the nucleus This contradicts the stability of matter (b) It cannot
explain the characteristic line spectra of atoms of different elements 5 |
9 | 2497-2500 | This contradicts the stability of matter (b) It cannot
explain the characteristic line spectra of atoms of different elements 5 Atoms of most of the elements are stable and emit characteristic
spectrum |
9 | 2498-2501 | (b) It cannot
explain the characteristic line spectra of atoms of different elements 5 Atoms of most of the elements are stable and emit characteristic
spectrum The spectrum consists of a set of isolated parallel lines
termed as line spectrum |
9 | 2499-2502 | 5 Atoms of most of the elements are stable and emit characteristic
spectrum The spectrum consists of a set of isolated parallel lines
termed as line spectrum It provides useful information about the
atomic structure |
9 | 2500-2503 | Atoms of most of the elements are stable and emit characteristic
spectrum The spectrum consists of a set of isolated parallel lines
termed as line spectrum It provides useful information about the
atomic structure 6 |
9 | 2501-2504 | The spectrum consists of a set of isolated parallel lines
termed as line spectrum It provides useful information about the
atomic structure 6 To explain the line spectra emitted by atoms, as well as the stability
of atoms, Niel’s Bohr proposed a model for hydrogenic (single elctron)
atoms |
9 | 2502-2505 | It provides useful information about the
atomic structure 6 To explain the line spectra emitted by atoms, as well as the stability
of atoms, Niel’s Bohr proposed a model for hydrogenic (single elctron)
atoms He introduced three postulates and laid the foundations of
quantum mechanics:
(a) In a hydrogen atom, an electron revolves in certain stable orbits
(called stationary orbits) without the emission of radiant energy |
9 | 2503-2506 | 6 To explain the line spectra emitted by atoms, as well as the stability
of atoms, Niel’s Bohr proposed a model for hydrogenic (single elctron)
atoms He introduced three postulates and laid the foundations of
quantum mechanics:
(a) In a hydrogen atom, an electron revolves in certain stable orbits
(called stationary orbits) without the emission of radiant energy (b) The stationary orbits are those for which the angular momentum
is some integral multiple of h/2p |
9 | 2504-2507 | To explain the line spectra emitted by atoms, as well as the stability
of atoms, Niel’s Bohr proposed a model for hydrogenic (single elctron)
atoms He introduced three postulates and laid the foundations of
quantum mechanics:
(a) In a hydrogen atom, an electron revolves in certain stable orbits
(called stationary orbits) without the emission of radiant energy (b) The stationary orbits are those for which the angular momentum
is some integral multiple of h/2p (Bohr’s quantisation condition |
9 | 2505-2508 | He introduced three postulates and laid the foundations of
quantum mechanics:
(a) In a hydrogen atom, an electron revolves in certain stable orbits
(called stationary orbits) without the emission of radiant energy (b) The stationary orbits are those for which the angular momentum
is some integral multiple of h/2p (Bohr’s quantisation condition )
That is L = nh/2p, where n is an integer called the principal
quantum number |
9 | 2506-2509 | (b) The stationary orbits are those for which the angular momentum
is some integral multiple of h/2p (Bohr’s quantisation condition )
That is L = nh/2p, where n is an integer called the principal
quantum number (c)
The third postulate states that an electron might make a transition
from one of its specified non-radiating orbits to another of lower
energy |
9 | 2507-2510 | (Bohr’s quantisation condition )
That is L = nh/2p, where n is an integer called the principal
quantum number (c)
The third postulate states that an electron might make a transition
from one of its specified non-radiating orbits to another of lower
energy When it does so, a photon is emitted having energy equal
to the energy difference between the initial and final states |
9 | 2508-2511 | )
That is L = nh/2p, where n is an integer called the principal
quantum number (c)
The third postulate states that an electron might make a transition
from one of its specified non-radiating orbits to another of lower
energy When it does so, a photon is emitted having energy equal
to the energy difference between the initial and final states The
frequency (n) of the emitted photon is then given by
hn = Ei – Ef
An atom absorbs radiation of the same frequency the atom emits,
in which case the electron is transferred to an orbit with a higher
value of n |
9 | 2509-2512 | (c)
The third postulate states that an electron might make a transition
from one of its specified non-radiating orbits to another of lower
energy When it does so, a photon is emitted having energy equal
to the energy difference between the initial and final states The
frequency (n) of the emitted photon is then given by
hn = Ei – Ef
An atom absorbs radiation of the same frequency the atom emits,
in which case the electron is transferred to an orbit with a higher
value of n Ei + hn = Ef
7 |
9 | 2510-2513 | When it does so, a photon is emitted having energy equal
to the energy difference between the initial and final states The
frequency (n) of the emitted photon is then given by
hn = Ei – Ef
An atom absorbs radiation of the same frequency the atom emits,
in which case the electron is transferred to an orbit with a higher
value of n Ei + hn = Ef
7 As a result of the quantisation condition of angular momentum, the
electron orbits the nucleus at only specific radii |
9 | 2511-2514 | The
frequency (n) of the emitted photon is then given by
hn = Ei – Ef
An atom absorbs radiation of the same frequency the atom emits,
in which case the electron is transferred to an orbit with a higher
value of n Ei + hn = Ef
7 As a result of the quantisation condition of angular momentum, the
electron orbits the nucleus at only specific radii For a hydrogen atom
it is given by
r
n
m
h
e
n =
2
2
20
2
4
π
πε
The total energy is also quantised:
4
2
2
2
0
8
n
me
E
n
εh
= −
= –13 |
9 | 2512-2515 | Ei + hn = Ef
7 As a result of the quantisation condition of angular momentum, the
electron orbits the nucleus at only specific radii For a hydrogen atom
it is given by
r
n
m
h
e
n =
2
2
20
2
4
π
πε
The total energy is also quantised:
4
2
2
2
0
8
n
me
E
n
εh
= −
= –13 6 eV/n2
The n = 1 state is called ground state |
9 | 2513-2516 | As a result of the quantisation condition of angular momentum, the
electron orbits the nucleus at only specific radii For a hydrogen atom
it is given by
r
n
m
h
e
n =
2
2
20
2
4
π
πε
The total energy is also quantised:
4
2
2
2
0
8
n
me
E
n
εh
= −
= –13 6 eV/n2
The n = 1 state is called ground state In hydrogen atom the ground
state energy is –13 |
9 | 2514-2517 | For a hydrogen atom
it is given by
r
n
m
h
e
n =
2
2
20
2
4
π
πε
The total energy is also quantised:
4
2
2
2
0
8
n
me
E
n
εh
= −
= –13 6 eV/n2
The n = 1 state is called ground state In hydrogen atom the ground
state energy is –13 6 eV |
9 | 2515-2518 | 6 eV/n2
The n = 1 state is called ground state In hydrogen atom the ground
state energy is –13 6 eV Higher values of n correspond to excited
states (n > 1) |
9 | 2516-2519 | In hydrogen atom the ground
state energy is –13 6 eV Higher values of n correspond to excited
states (n > 1) Atoms are excited to these higher states by collisions
with other atoms or electrons or by absorption of a photon of right
frequency |
9 | 2517-2520 | 6 eV Higher values of n correspond to excited
states (n > 1) Atoms are excited to these higher states by collisions
with other atoms or electrons or by absorption of a photon of right
frequency Rationalised 2023-24
Physics
304
8 |
9 | 2518-2521 | Higher values of n correspond to excited
states (n > 1) Atoms are excited to these higher states by collisions
with other atoms or electrons or by absorption of a photon of right
frequency Rationalised 2023-24
Physics
304
8 de Broglie’s hypothesis that electrons have a wavelength l = h/mv gave
an explanation for Bohr’s quantised orbits by bringing in the wave-
particle duality |
9 | 2519-2522 | Atoms are excited to these higher states by collisions
with other atoms or electrons or by absorption of a photon of right
frequency Rationalised 2023-24
Physics
304
8 de Broglie’s hypothesis that electrons have a wavelength l = h/mv gave
an explanation for Bohr’s quantised orbits by bringing in the wave-
particle duality The orbits correspond to circular standing waves in
which the circumference of the orbit equals a whole number of
wavelengths |
9 | 2520-2523 | Rationalised 2023-24
Physics
304
8 de Broglie’s hypothesis that electrons have a wavelength l = h/mv gave
an explanation for Bohr’s quantised orbits by bringing in the wave-
particle duality The orbits correspond to circular standing waves in
which the circumference of the orbit equals a whole number of
wavelengths 9 |
9 | 2521-2524 | de Broglie’s hypothesis that electrons have a wavelength l = h/mv gave
an explanation for Bohr’s quantised orbits by bringing in the wave-
particle duality The orbits correspond to circular standing waves in
which the circumference of the orbit equals a whole number of
wavelengths 9 Bohr’s model is applicable only to hydrogenic (single electron) atoms |
9 | 2522-2525 | The orbits correspond to circular standing waves in
which the circumference of the orbit equals a whole number of
wavelengths 9 Bohr’s model is applicable only to hydrogenic (single electron) atoms It cannot be extended to even two electron atoms such as helium |
9 | 2523-2526 | 9 Bohr’s model is applicable only to hydrogenic (single electron) atoms It cannot be extended to even two electron atoms such as helium This model is also unable to explain for the relative intensities of the
frequencies emitted even by hydrogenic atoms |
9 | 2524-2527 | Bohr’s model is applicable only to hydrogenic (single electron) atoms It cannot be extended to even two electron atoms such as helium This model is also unable to explain for the relative intensities of the
frequencies emitted even by hydrogenic atoms POINTS TO PONDER
1 |
9 | 2525-2528 | It cannot be extended to even two electron atoms such as helium This model is also unable to explain for the relative intensities of the
frequencies emitted even by hydrogenic atoms POINTS TO PONDER
1 Both the Thomson’s as well as the Rutherford’s models constitute an
unstable system |
9 | 2526-2529 | This model is also unable to explain for the relative intensities of the
frequencies emitted even by hydrogenic atoms POINTS TO PONDER
1 Both the Thomson’s as well as the Rutherford’s models constitute an
unstable system Thomson’s model is unstable electrostatically, while
Rutherford’s model is unstable because of electromagnetic radiation
of orbiting electrons |
9 | 2527-2530 | POINTS TO PONDER
1 Both the Thomson’s as well as the Rutherford’s models constitute an
unstable system Thomson’s model is unstable electrostatically, while
Rutherford’s model is unstable because of electromagnetic radiation
of orbiting electrons 2 |
9 | 2528-2531 | Both the Thomson’s as well as the Rutherford’s models constitute an
unstable system Thomson’s model is unstable electrostatically, while
Rutherford’s model is unstable because of electromagnetic radiation
of orbiting electrons 2 What made Bohr quantise angular momentum (second postulate) and
not some other quantity |
9 | 2529-2532 | Thomson’s model is unstable electrostatically, while
Rutherford’s model is unstable because of electromagnetic radiation
of orbiting electrons 2 What made Bohr quantise angular momentum (second postulate) and
not some other quantity Note, h has dimensions of angular
momentum, and for circular orbits, angular momentum is a very
relevant quantity |
9 | 2530-2533 | 2 What made Bohr quantise angular momentum (second postulate) and
not some other quantity Note, h has dimensions of angular
momentum, and for circular orbits, angular momentum is a very
relevant quantity The second postulate is then so natural |
9 | 2531-2534 | What made Bohr quantise angular momentum (second postulate) and
not some other quantity Note, h has dimensions of angular
momentum, and for circular orbits, angular momentum is a very
relevant quantity The second postulate is then so natural 3 |
9 | 2532-2535 | Note, h has dimensions of angular
momentum, and for circular orbits, angular momentum is a very
relevant quantity The second postulate is then so natural 3 The orbital picture in Bohr’s model of the hydrogen atom was
inconsistent with the uncertainty principle |
9 | 2533-2536 | The second postulate is then so natural 3 The orbital picture in Bohr’s model of the hydrogen atom was
inconsistent with the uncertainty principle It was replaced by modern
quantum mechanics in which Bohr’s orbits are regions where the
electron may be found with large probability |
9 | 2534-2537 | 3 The orbital picture in Bohr’s model of the hydrogen atom was
inconsistent with the uncertainty principle It was replaced by modern
quantum mechanics in which Bohr’s orbits are regions where the
electron may be found with large probability 4 |
9 | 2535-2538 | The orbital picture in Bohr’s model of the hydrogen atom was
inconsistent with the uncertainty principle It was replaced by modern
quantum mechanics in which Bohr’s orbits are regions where the
electron may be found with large probability 4 Unlike the situation in the solar system, where planet-planet
gravitational forces are very small as compared to the gravitational
force of the sun on each planet (because the mass of the sun is so
much greater than the mass of any of the planets), the electron-electron
electric force interaction is comparable in magnitude to the electron-
nucleus electrical force, because the charges and distances are of the
same order of magnitude |
9 | 2536-2539 | It was replaced by modern
quantum mechanics in which Bohr’s orbits are regions where the
electron may be found with large probability 4 Unlike the situation in the solar system, where planet-planet
gravitational forces are very small as compared to the gravitational
force of the sun on each planet (because the mass of the sun is so
much greater than the mass of any of the planets), the electron-electron
electric force interaction is comparable in magnitude to the electron-
nucleus electrical force, because the charges and distances are of the
same order of magnitude This is the reason why the Bohr’s model
with its planet-like electron is not applicable to many electron atoms |
9 | 2537-2540 | 4 Unlike the situation in the solar system, where planet-planet
gravitational forces are very small as compared to the gravitational
force of the sun on each planet (because the mass of the sun is so
much greater than the mass of any of the planets), the electron-electron
electric force interaction is comparable in magnitude to the electron-
nucleus electrical force, because the charges and distances are of the
same order of magnitude This is the reason why the Bohr’s model
with its planet-like electron is not applicable to many electron atoms 5 |
9 | 2538-2541 | Unlike the situation in the solar system, where planet-planet
gravitational forces are very small as compared to the gravitational
force of the sun on each planet (because the mass of the sun is so
much greater than the mass of any of the planets), the electron-electron
electric force interaction is comparable in magnitude to the electron-
nucleus electrical force, because the charges and distances are of the
same order of magnitude This is the reason why the Bohr’s model
with its planet-like electron is not applicable to many electron atoms 5 Bohr laid the foundation of the quantum theory by postulating specific
orbits in which electrons do not radiate |
Subsets and Splits