Question

Alkali metals are strong _____ agents because they ____ electrons to complete their octet.

• A. reducing
• B. lose

Answer 1

• Valence electrons of an element is defined as the number of electrons present in the outermost shell of that element.
• Valence electrons in any element in Group 1, 2, and 13 to 18 can be predicted by its Group number. Example, elements in Group 1 or Group IA have 1 valence electron.
• Elements present in Group 1 of the periodic table except Hydrogen (H) are termed as alkali metals. It includes Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr).
• Since alkali metals are present in Group 1, they all have one valence electron in their outermost shell.
• Reducing agents are the ones that themselves undergo oxidation (loss of electron) and reduce the other species.
• Since alkali metals have only one valence electron, they will readily lose that electron and undergo oxidation to complete their octet (eight electrons in the valence shell). Hence, they are classified as strong reducing agents.
• Example, the electronic configuration of Sodium is 2, 8, 1. Sodium (Na) readily loses one electron to form a Sodium ion (Na⁺). The electronic configuration of Sodium ion becomes 2,8. Since Sodium ion has a complete octet and therefore, Sodium acts as a strong reducing agent.

$\mathrm{Na}\left(\mathrm{s}\right)\to {\mathrm{Na}}^{+}\left(\mathrm{aq}\right)+{\mathrm{e}}^{-}$

• Alkali metals are strong reducing agents because they lose electrons to complete their octet.