Question

If the atomic number of an element is 17 and it has 18 neutrons in its atom, its valency will be _________.

• A. 17
• B. 18
• C. 7
• D. 1

Answer 1

The correct option is D 1

For a neutral atom,
Atomic number = Number of protons = Number of electrons

Electronic configuration for an atom with 17 electrons in it is (2,8,7)

Valence electrons are the electrons present in the outermost shell of an atom.
$\therefore$ The number of valence electrons = 7

Valency of an atom with more than 4 valence electrons = 8 - Number of valence electrons
$\therefore$ Valency = 8 - 7 = 1