Question

The electronic configuration of an element is $'X'$ is $2,8,6$ . To which group and period of the modern periodic table do $'X'$ belong, state its valency and justify your answer in each case.

Answer 1

The electronic configuration of an element is given. Based on the number of electrons the atomic number can be determined. From this atomic number the period, group and valency can be determined. Valency is the number of electrons that can be gained or lost.

Complete Step By Step Answer:
The modern periodic table is the representation of elements arranged according to the order of atomic numbers in vertical columns and horizontal rows. The vertical columns were known as groups and the horizontal rows were known as periods. There are $7$ periods and $18$ groups in the periodic table.
The electronic configuration of an element is $2,8,6$ . Thus, the number of electrons is $16$ . In any element the number of electrons and protons are equal. The atomic number was represented by the number of protons. Thus, the atomic number of an element is $16$ .
The element with atomic number $16$ is Sulphur, and has the chemical symbol $S$ . It belongs to the ${3^{rd}}$ period and the ${16^{th}}$ group. As the outer valence electrons are six, it tries to gain two electrons. Thus, the valency is $- 2$ .

Note:
Being a non-metal, sulfur always tries to attract electrons. Thus, the valency is represented by a negative number which means it exists as a negative ion. The negative ion is known as an anion. In chemical compounds, sulfur exists as an anion.