Answer :
Sodium is part of the alkali metal group because it has properties that have periodic patterns relating to the rest of the group. It is in it's period because of it's energy level and the amount of electrons on that level. It is also apart of it's group because of how many valence electrons it has.
Explanation:
It is known that the atomic number of sodium is 11 and its electronic distribution is 2, 8, 1.
As the number of rows (called periods) in the periodic table represent the number of shells present in an element.
Since, sodium element have only two shells. Therefore, sodium lies in row 2 of the periodic table.
Also, the elements which contain same number of valence electrons lie in the same group.
Therefore, sodium belongs to group 1 and elements of the group 1 are also known as alkali metals.
Thus, we can conclude that in the periodic table sodium lies in period 2 and group 1.
