Question

The atomic numbers of few elements are given below. Calculate the number of valence electrons in each case and find the value of X, Y and Z.

Elements	Atomic number	Number of valence electrons
Carbon	6	X
Nitrogen	7	Y
Oxygen	8	Z

• A. X-4; Y-6; Z-5
• B. X-4; Y-2; Z-5
• C. X-2; Y-5; Z-6
• D. X-4; Y-5; Z-6

Answer 1

The correct option is D X-4; Y-5; Z-6

$\bullet$ The electronic configurations of the given elements are:$$\begin{array}{cc}\text{Element}& \text{Electronic configuration}\\ \text{Carbon}& \text{2, 4}\\ \text{Nitrogen}& \text{2, 5}\\ \text{Oxygen}& \text{2, 6}\end{array}$$
$\bullet$ Valence electrons are the electrons present in the outermost (valence) shells of the atom.

$\bullet$ Thus, the number of valence electrons in:
Carbon = 4
Nitrogen = 5
Oxygen = 6