Among CaH 2 , BeH 2 , BaH 2 , what is the order of ionic character?

Among CaH2, BeH2, BaH2, what is the order of ionic character?
  1. BeH2<BaH2<CaH2
  2. CaH2<BeH2<BaH2
  3. BeH2<CaH2<BaH2
  4. BaH2<BeH2<CaH2

Solution

BeH2<CaH2<BaH2
The size of the elements follow the order: Be<Ca<Ba
Smaller the size of cation, more will be its polarizing power. Thus, a higher polarization will lead to a greater covalent character, or the least ionic character. Hence, BeH2 will be least ionic. Top to bottom size of cation increase so covalent character decrease and ionic character increases.

Asked in: NEET 2018

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