Question

How do you calculate the number of valence electrons in an arsenic atom?

Answer 1

Valence electrons in an arsenic atom:

• The valence electrons of any element are represented as the total number of electrons present in its valence shell.
• Arsenic is in group 15, and for this, the atomic number is 33, which means arsenic atoms have 33 protons and, if neutral, 33 electrons.
• we can calculate the number of electrons present in the valence shell by knowing the electronic configuration of Arsenic
• The electron configuration for the ground-state neutral arsenic atom is given by;

$1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}3{\mathrm{d}}^{10}4{\mathrm{s}}^{2}4{\mathrm{p}}^3\mathrm{or}\left[\mathrm{Ar}\right]3{\mathrm{d}}^{10}4{\mathrm{s}}^{2}4{\mathrm{p}}^3$

• As, it has 5 electrons in its outermost valence shell ($4^{th}$), its atoms have 5 valence electrons.

Hence, the number of valence electrons in an arsenic atom can be calculated as mentioned above, which is given by;5 valence electrons.