Justify the following statements:
(a) Cations are smaller in size than the corresponding atom.
(b) Size of the atom increases as we move down a group.
© Atomic size decreases as we move across a period.
(a) Because cations are formed by loss of valence electrons. This decreases the nuclear charge and thus size of cations decreases.
(b) Because new shells are being added as we go down the group.
© It is due to an increase in nuclear charge which tends to pull the electrons closer to the nucleus and reduces the size of the atom.