question_answer

  The following data represents the distribution of electrons, protons and neutrons in atoms of four elements A, B, C, D

Particles	Electrons	Protons	Neutrons
A B C D	10 11 12 13	10 12 12 14	10 11 12 13

  Answer the following questions. (i)Write the electronic distribution in atoms of element A and D. (ii) Element A is an inert gas. Why? (iii) What is the valency of element C? [cbse 2012]

Answer:

                              (a)Valency of M = 3 because it combines with three atoms of hydrogen. (b)Valency of chlorine (Cl 2, 8, 7) = 8 ? 7 = 1 Valency of sulphur (S 2, 8, 6) = 8 ? 6 = 2 (c) Protium, ,Deuterium, ,Tritrium