Three elements $X,Y$ and Z belong to 17th group but to 2nd, 3rd and 4th period respectively. A number of the valence electron in Y is 7.Find the number of the valence electron in X and Z.

Q. An element $X$ belongs to $3^{rd}$ period and group $16$ of the Modern Periodic Table.
Determine the number of valence electrons and the valency of X?

Q. An element X belongs to group 2 and another element Y belongs to group 15 of the periodic table:

(a) What is the number of valence electron in X?
(b) What is the valency of X?
(c) What is the number of valence electrons in Y?
(d) What is the valency of Y?
Explain how you have arrived at your answers.

Q. An element $X$ belongs to 3rd period and group 2 of the periodic table. State:
(a) The number of valence electrons
(b) The valency
(c) Whether it is metal or a nonmetal.

Q. Elements X, Y, and Z have atomic numbers 6, 9, and 12 respectively. Which one has four electrons in its valence shell?

Q. An element belongs to the 3rd period and Group II of the periodic table.
Number of valence electrons are ______________.