Question

An element Y is in second period and group 16 of the periodic table:

(i) Is it a metal or non-metal?
(ii) What is the number of valence electrons in its atom?
(iii) What is its valency?
(iv) What is the name of the element?
(v) What will be the formula of the compound formed by Y with sodium?

Answer 1

(i) The element Y is a non-metal as all the elements of group 16 are non-metals.

(ii) The number of valence electrons of the element = Group number - 10
                                                                            = 16-10 = 6.
(iii) Valency of Y = 8- number of valence electrons
                         = 8 - 6 = 2.
(iv) The name of the element is oxygen as it is the first element in group 16.

(v) Sodium is a group 1 element with a valency of 1. The valency of Y is 2. Therefore, when two atoms of sodium (Na) combine with one atom of Y, the formula of the resulting ionic compound is Na₂Y.