To show the electron configuration for an atom, when would it be better to use an orbital notation than to use a written configuration with numbers, letters, and superscripts?
a.when the aim is to use less space
b.when the aim is to show electron spins
c.when the aim is to show orbital shapes in subshells
d.when the aim is to show electron distributions in shells

The answer is D.when the aim is to show electron distributions in shells. This is because there are some instances when elements don't possess a regular or normal electron configuration. There are those who have special electron configurations wherein a lower subshell isn't completely filled before occupying a higher subshell. It is best to visualize such cases using the orbital notation.

BA(OH)2 (Barium hydroxide)

Barium hydroxide is a chemical compound with the chemical formula Ba(OH)₂ₓ. The monohydrate, known as baryta or baryta-water, is one of the principal compounds of barium.