CBSE Class 9 Answered

(a) A cation is a positively charged atom. It is formed by the loss of one or more electrons by an atom.

(b) A cation has more number of protons than electrons. Taking sodium atom as example,

Sodium atom loses one electron to form sodium ion. So, the number of protons and electrons in sodium atom and sodium ion will be:

Sodium atom: No. of protons = 11 (+ charge) ; No. of electrons = 11 (- charge)

Sodium ion: No. of protons = 11 (+ charge) ; No. of electrons = 10 (- charge)

So, Overall charge on sodium atom = 11 - 11 = 0

Overall charge on sodium ion = 11 - 10 = +1

Hence, sodium cation has a positive charge.