Question

How many valence electrons does iron have?

Answer 1

Valence electrons:

• The electrons which are distributed in the outermost shell of the atom are called valence electrons.
• These valence electrons can form a chemical bond only if the outer shell remains unclosed.

Valence electrons in an Iron($\left(\mathrm{Fe}\right)$ atom:

• The element Iron$\left(\mathrm{Fe}\right)$ is in the fourth period and belongs to the $\mathrm{d}$-block (group 8).
• The atomic number of Iron$\left(\mathrm{Fe}\right)$ is 26.
• The electronic configuration of Iron$\left(\mathrm{Fe}\right)$ can be written as $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^6$
• The valence electrons are the sum of the electrons in the outermost shell, that is six $3\mathrm{d}$ electrons and two $4\mathrm{s}$ electrons which gives a total of eight valence electrons.

Therefore, the valence electron in an Iron($\left(\mathrm{Fe}\right)$atom is 8.