Question

A 1s²2s²2p6 3s²3p5
D 1s²2s²2p63s²3p6 4s2
write the chemical formula of th compound formed by the elemant A and B​

Answer 1

Answer:

should be CaCl2

Explanation:

A has atomic no 17

B has atomic no 20

So A is chlorine and B is calcium

compound formed by these two compounds is CaCl2

Answer 2

Answer:

CaCl₂

Explanation:

A: 1s² 2s² 2p⁶ 3s² 3p⁵ is the electronic configuration of Chlorine.

B: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² is the electronic configuration of Calcium.

Valency means the number of electrons an atom can lose or gain to attain noble gas configuration. The valency of Chlorine is 1 and of Calcium is 2. This means Chlorine must gain an electron to attain stability and Calcium must lose two electrons to do the same. Thus, two molecules of Chlorine will react with one molecule of Calcium to form an Ionic compound called Calcium Chloride.