Question

How do the valence electron configurations of the alkali metals compare with each other?

Answer 1

Hint: The valence electrons are defined as the electrons which are present in the out most electronic configuration of the chemical element. The valence electrons take part in chemical bonding. You must know the atomic number and the electronic configuration of the alkali metal to determine the answer.

Complete step by step answer:
Alkali metals are those metals which are present in the s-block elements which occupy the left side of the periodic table.
The alkali refers to the basic nature of the metal hydroxides. These compounds are referred to as alkali metals because they react with water to form metal hydroxide which is a strong base. The property of a strong base is that it neutralizes strong acid to form salt.
The alkali metals have electronic configuration corresponding to [Noble gas]$n{s}^1$. The alkali metals are present in the first column of the periodic table and are lithium (Li), Sodium (Na), potassium (K), Rubidium (Ru), Cesium (Cs) and Francium (Fr). Francium is a radioactive element.
When we see the electronic configuration of all the alkali metal, we can observe that the outermost orbital contains one electron. So they lose their one electron to form a cation and a stable noble gas configuration.
Lithium (Li):$[He]2s^1$
Sodium (Na):$[Ne]3s^1$
Potassium (K):$[Ar]4s^1$
Rubidium (Rb): $[Kr]5s^1$
Caesium (Cs): $[Xe]6s^1$
Francium (Fr): $[Rn]7s^1$
The outermost electronic configuration of the alkali metal contains 1 valence electrons which is the similar characteristic shown by all the alkali metal.

Note: Hydrogen is also present in the first column but is not considered as the alkali metal as it is mostly present in a gas form and is not a metal but shows similar characteristics like alkali metal.