Question

Two elements A and B have atomic number 19 and 17 respectively. 1)what is the nature of A and B .2)write electrovalency of A and B 3)write covalency of A and B .4)write molecular formulae of the compound formed between A and B.

Answer 1

A is potassium

B is chlorine

1)A is a metal

  B is a non metal (gas)

2)A loses an electron so -1

  B gains an electron so +1

3)A does not exhibit covalency

  B it has a covalency of one electron so 1

4)KCl or potassium chloride