What do you expect the nature of hydrides is, it formed by elements of atomic numbers `15,19,23` and `44` with dihydrogen? Compare their behaviour towards water.

Explanation

(i) Element with Z = 15 is a non-metal (i.e., P) and hence form covalent hydride `(PH)_3`
(ii) Element with Z = 19 is an alkali metal (K) and hence form ionic or saline hydride `(K^+ H^(-))`.
(iii) Element with Z = 23 is a transition element (i.e., V) of group 5 and hence forms metallic or interstitial hydride (i.e., `VH_(1.6)`).
(iv) Element with Z = 44 is a transition metal (Ru) of group 8 and therefore , it does not form any hydride.
Behaviour towards water. Only ionic hydrides (e.g. `K^(+)H^(-))` react with water evolving `H_2` gas as `2KH (s) + underset("water")(2H_2 O(l)) to 2KOH (aq) + 2H_2 (l))`