Explain the factors favourable for the formation of cation in lonic bond.

Explanation

Factors that favour the formation of ionic bond :
a) Factors favorable for the cation formation :
i) Low 1P : Atom with low IP loses electrons readily. So it forms cations readily .
`K^(+)(IP 496 "KJ mol"^(-1))` ion forms.readily than `Na^(+)(IP 520"KJ mol"^(-1))` ion .
ii) Low charge on the ion : Formation of an ion with low charge requires, lower IP than formation of an ion with high charge. Thus out of `Na^(+), Mg^(2+)` and `Al^(3+)` , the ease. of formation of these ions is `Na^(+)gtMg^(+)gtAl^(3+)`
iii) Large atomic size : The force of attraction between the nucleus and the valence electrons is less in case of larger atoms than in case of smaller atoms So larger atoms. can lose electrons more readily than smaller atoms.
Ex : `Cs^(+)` is formed more easily that any of the other alkali metalions .
iv) Formation of : cation with inert gas configuration : Cations with inert gas .configuration are easily formed.
Ex : Out of `Ca^(2+)` and `Zn^(2+), Ca^(2+)` ion `(2,8,8)` is easily formed than `Zn^(2+)` ion `(2,8,18)` with pseudo inert gas configuration .
b) Factors favourable for anion-formation :
i) High.EN and high EA : An atom with high EN and high EA has a greater tendency to accept electrons and so it can readily form anion.
Ex : The ease of formation of anions is `FgtO^(2-)gtN^(-3)`
ii) Small atomic size : Small atoms can hold strongly the electrons gained by it.
Ex: The order of ionic nature in halide ions is `F^(-)gtCl^(-)gtBr^(-)gtl^(-)`
F is the smallest and I is the largest atom, among them.

iii) Low charge on the ion : Stability of ion decreases with increase in its charge. Anion with low-ve charge is formed more readily than anion with high -ve charge.
Ex : `F^(-)` ion is easily formed that `O^(2-)` ion -