Sodium Atom Na Forms Positive Ion Na But Chlorine Atom Cl Does Not Form Positive Cl Ion

Sodium atom, Na forms the positive ion Na+, but chlorine atom Cl, does not form the positive Cl+ ion.

Answers:

Sodium is the first element of period 3 whereas chlorine is the last but one element of the same period. Since ionization potential increases across a period, the ionization potential of Na is much smaller than that of Cl. Hence, Na can lose an electron to form Na⁺ ion whereas Cl cannot lose an electron to form Cl⁺ ion.