elements in the same group on the periodic table of elements have similar properties
one_of_chemical_elements is oxygen. one_of_chemical_elements is not radon. each_element_in_periodic_table has number_associated_with different_elements has not different_mechanical_properties different_elements has different_mechanical_properties molecule is group_of_similar_atoms. one_of_chemical_elements is hydrogen. one_of_chemical_elements is not hydrogen. one_of_chemical_elements is not luterium. one_of_chemical_elements is chromium.