State Fajan’s Rules and give suitable examples?

Fajan’s rules are useful to predict the nature of bond formed between two atoms.
i) As the cations size increases the ionic nature of bond also increase.
Ex : Increasing order of size of cations is
${\mathrm{Li}}^{+}<{\mathrm{Na}}^{+}<{\mathrm{K}}^{+}<{\mathrm{Rb}}^{+}<{\mathrm{Cs}}^{+}$
So, ionic nature order is
LiCl < NaCl < KCl < RbCl < CsCl.
ii) As the anionic size decreases the Ionic nature
of bond also increases
Ex : Ionic nature order is
${\mathrm{CaF}}_2>{\mathrm{CaCl}}_2>{\mathrm{CaBr}}_2>{\mathrm{Cal}}_2$ it is due to the order of anion size ${\mathrm{F}}^{-}<{\mathrm{Cl}}^{-}<{\mathrm{Br}}^{-}<{\mathrm{I}}^{-}$
iii) As the as charge on cation or anion decreases the ionic nature of bond increases.
NaCl is ionic in nature (due to less charge on Na⁺¹ ion)
AlCl₃ is covalent in nature (due to highly charged Al⁺³)
iv) Cations with inert gas configuration forms ionic compounds. But cations with pseudo inert gas configuration forms covalent compounds.
Ex : NaCl is ionic but ZnCl₂ is covalent in nature.
Na⁺(2,8) ; Zn²⁺ (2, 8, 18)