Question

How many valence electrons does Iodine 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 Iodine atom:

• The element Iodine$\left(\mathrm{I}\right)$ is in the fifth period and belongs to the Alkali metals group (group 17).
• The atomic number of Iodine$\left(\mathrm{I}\right)$ is 53.
• The electronic configuration of Iodine$\left(\mathrm{I}\right)$ can be written as $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^{10}4{\mathrm{p}}^{6}5{\mathrm{s}}^{2}4{\mathrm{d}}^{10}5{\mathrm{p}}^5$
• The valence electrons are the sum of the electrons in the outermost shell, that is two $5\mathrm{s}$ electrons and five $5\mathrm{p}$ electrons which gives a total of seven valence electrons.

Therefore, the valence electron in an Iodine$\left(\mathrm{I}\right)$ atom is 7.