Question

This question refers to isolated gaseous atoms.
In which atom are all electrons paired?
A. Ba
B. Br
C. S
D. Si

And why ?

Answer 1

Answer:

Sulphur is the right answer

Answer 2

Isolated gaseous atom

Explanation:

The word isolated means seperate or kept apart .

When an atom is free from other atoms in gaseous state, is called as "isolated gaseous atom".

The lowest energy state possible for an atom is ground state.

The electron configuration of an atom is the arrangement of electrons distributed among the orbital shells and subshells the electronic  configuration is used to describe the orbitals of an atom in its ground state

1.The configuration for the free atoms is:

               Ba - [Xe] 6s²

             Br - [Ar] 3d¹⁰4s²4p⁵

             S - [Ne] 3s²3p4

             Si - [Ne] 3s²3p²

Thus:

Answer is A

Barium has (no unpaired) electrons.