Illustrate how sodium sulfide (Na2S) is formed. Class 9

Illustrate how sodium sulfide (Na₂S) is formed. Class 9

Question 1.

Illustrate how sodium sulfide (Na₂S) is formed. Class 9

Answer:

Sodium (atomic number 11) has electronic configuration 2, 8, 1. It has 1 valence electron, which it loses to form Na⁺: Na → Na⁺ + e^-

Sulfur (atomic number 16) has electronic configuration 2, 8, 6. It has 6 valence electrons and needs 2 more electrons to complete its octet. It gains 2 electrons to form S^2-: S + 2e^- → S^2-

Two sodium atoms each lose one electron (total 2 electrons) which are gained by one sulfur atom: 2Na → 2Na⁺ + 2e^- S + 2e^- → S^2-

The two Na+ ions and one S^2- ion are held together by electrostatic force of attraction (ionic bond) to form sodium sulfide: 2Na⁺ + S^2- → Na₂S.

(Page 177)

Question 2.

Name the following: Class 9

(i) CO₂ ____________

(ii) NO₂ ____________

(iii) SF₆ ____________

(iv) PCl₃ ____________

Answer:

(i) CO₂ - Carbon dioxide

(ii) NO₂ - Nitrogen dioxide

(iii) SF₆ - Sulfur hexafluoride

(iv) PCl₃ - Phosphorus trichloride