Astate in which all of the electrons in an atom have their lowest possible energies.

If an atom, ion, or molecule is at the lowest possible energy level, it and its electrons are said to be in the ground state. If it is at a higher energy level, it is said to be excited, or any electrons that have higher energy than the ground state are excited.

The significant figures in 46 is two.
The first is 4
And the second is 6