Question

Give reason for the following:
Alkali metals are good reducing agents.

Answer 1

Hint: Alkali metals consists of the chemical elements lithium$(Li)$, sodium$(Na)$, potassium$(K)$, rubidium$(Rb)$, caesium$(Cs)$and francium$(Fr)$. Together with hydrogen they constitute group 1 which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital, this shared electron configuration results in their having very similar characteristic properties.

Complete step by step solution:
Reducing agents are those compounds or elements which can reduce others and get oxidized themselves. Strong reducing agents easily lose or donate electrons. An atom with relatively large atomic radius tends to be better reductant. In such species the distance from the nucleus to the valence electron is so long that these electrons are not strongly attached. These elements tend to be strong reducing agents. Good reducing agents tend to consist of atoms with a low electronegativity, the ability of an atom or molecule to attract bonding electrons and species with relatively small ionization energies serve as good reducing agents too.

Alkali metals act as strong or good reducing agents, the reason behind this is that alkali metals have only one valence electron in their valence shell.
So, because of this it is easy for them to lose an electron and attain nearest noble gas configuration and become more stable then they were earlier.
Thus, they can lose an electron and get oxidized themselves, hence reducing other compounds.
So, because of these reasons the alkali metals are termed as good reducing agents.

Note:
The alkali metals are all shiny, soft, highly reactive metals at standard temperature and pressure and readily lose their outermost electron to form cations with charge +1. They can be cut easily with a knife due to their softness, exposing a shiny surface that tarnishes rapidly in air due to oxidation by atmospheric moisture and oxygen. Because of their high reactivity they must be stored under oil to prevent reaction with air and are found naturally only in salts and never as the free elements.