Question

What group is sodium in?

Answer 1

Sodium is the sixth most abundant element on the earth. It belongs to a group of elements known as alkali metals as they react with water and forms an alkali. Alkali metals possess only 1 electron in their valence shell and come under the s-block elements.

Complete answer:
The modern periodic table contains 18 groups and 7 periods. The elements present in one group have the same number of valence electrons. The number of valence electrons of elements is always equal to their group number.
Group 1 elements have 1 valence electron and group 2 elements have 2 valence electrons and so on. For group numbers 13, 14, and so on, the number of valence electrons is equal to $\left( 10-13=3 \right)$, $\left( 10-14=4 \right)$, and so on.
Sodium (Na) is a very soft silvery-white metal. It occurs abundantly in nature, especially as common salt—sodium chloride (NaCl)—which constitutes about 80 percent of the dissolved constituents of seawater.
Its atomic number is 11. It means that it possesses 11 protons and 11 electrons. So, the electronic configuration of sodium can be written as:
$\text{Na}=1{{\text{s}}^{2}}2{{\text{s}}^{2}}2{{\text{p}}^{6}}3{{\text{s}}^{1}}$
Now, we can see that sodium has 1 electron in its outermost shell (3s). So, the number of valence electrons in sodium is 1.
Hence, the sodium element belongs to group 1 of the periodic table.

Note:
The chemical properties of elements depend upon the number of electrons that are present to participate in chemical reactions. That is, the number of valence electrons determines the characteristic properties of any element. Thus, the elements of the same group show similar physical and chemical properties as they have an identical number of valence shell electrons.