Rubidium and cesium have similar chemical

properties because, in the ground state, the

atoms of both elements each have

(1) one electron in the outermost shell

(2) two electrons in the outermost shell

(3) one neutron in the nucleus

(4) two neutrons in the nucleus

Rubidium and cesium have similar chemical properties because in the ground state the atoms of both elements each have one electron in the outermost shell. The correct option is A. The two elements belong to group one of the periodic table; all elements in this group have only one electron in their outmost shell which they easily give away to other elements during chemical reactions in order to attain octet structure.