Use condensed electron configurations and Lewis

Solution 17P

Here we have to use condensed electron configurations and Lewis electron-dot symbols to depict the ions formed from each of the following atoms, and predict the formula of their compound.

Condensed electron configuration:- When the electronic configuration is written by writing the symbol of noble gas in bracket along with the valence shell electron, such electronic configuration is called as condensed electron configuration.

Lewis dot structure:- Lewis dot structure is also called as electron dot structure which involves the representation of valence shell electrons by cross or dot on the symbol of the atom. In his structure the symbol of the atom indicates the inner shell electron and the nucleus.

Step 1

(a) Cs and S

It is known that metal  is always lose electron whereas nonmetal will gain electron.

Here Cs is a metal  and S is a nonmetal.

The condensed electron configuration of  Cs is :- 55Cs [Xe] 6s1

The condensed electron configuration of S :- 16 S [Ne] 3s2 3p4 

Cs has 1 electron in its valence shell, hence it can donate 1 electrons and become Cs+. Similarly the nonmetal S atom has 6 electrons in its valence shell, by gaining two electrons it will be chemically stable .

In order to form a compound, 1 S atom  required to gain 2 electrons from two Cs atom. It is shown below,

Thus the compound formed by Cs and S is Cs2S.