He
discovered alpha-rays and
beta-rays Along 
with
Federick Soddy, he created
the modern theory of
radioactivity He studied
the ‘emanation’ of thorium
and discovered a new noble
gas, an isotope of radon,
now known as thoron By
scattering alpha-rays from
the 
metal 
foils, 
he
discovered the atomic
nucleus and proposed the
plenatery model of the
atom