Question

The atom of an element has electronic configuration 2, 8, 8, 2.
(a) What is the atomic number of the element?
(b) To which of the following elements would it be chemically similar? (Atomic numbers of elements are given in brackets)
He (2); O (8); Mg (12); K (19)
​Give reason for your choice.

Answer 1

(a) The atomic number of an element will be 20.

(b) Electronic configuration of the element is 2, 8, 8, 2. So, from this, we can conclude that it belongs to the second group of the periodic table. In modern periodic table elements with similar properties are placed in the same group. Out of the given options magnesium belongs to the same group as the electronic configuration of magnesium is 2, 8, 2.