Question

An element with electronic configuration 2,8,2, belongs to which period and group.

Answer 1

Electronic configuration: It is the distribution of the electrons in the atomic orbitals around the nucleus in an atom.

Given electronic configuration is$2,8,2$.

Step-1: Find out the number of valence electrons.

Valence electrons: The electrons present in the outermost shell of an atom are known as the valence electrons.

• The number of valence electrons present in an atom indicates the group number in which the element is present in the long form of the periodic table.
• From the electronic configuration, it can be seen that $2$ electrons are present in the outermost shell.
• Therefore, the group number of the element is $2$.

Step-2: Find out the number of shells.

• The number of shells present in an atom indicates the period number in which the element is present in the long form of the periodic table.
• From the electronic configuration, it can be seen that $3$ electronic shells are present in the atom to accommodate 12 electrons.
• Therefore, the period number of the element is $3$.
• The element with electronic configuration 2,8,2 is located in $3^{\mathrm{rd}}$ period and $2^{\mathrm{nd}}$ group and the element is Magnesium $\left(\mathrm{Mg}\right)$.