Give reasons for the following:
a] Metals have a tendency to form cations.
b] Fluorine atom is smaller than chlorine atom.
c] Non-metals have a tendency to gain electrons.

Explanation

a) Since metals have 1-3 valence electrons, it is easier to lose and attain a noble gas configuration rather than gain electrons. Hence, they tend to form cations.
  b] Fluorine atom has only two electron shells while chlorine atom has three. Thus, Fluorine atom is smaller.
c] Non-metals have 5-8 valence electrons (except carbon which has 4 valence electrons). It is easier for them to gain additional electrons and attain noble gas configuration while bonding rather than lose electrons. Hence, nonmetals tend to gain electrons.