Question

What can be added to an atom to cause a nonvalence electron in the atom to temporarily become a valence electron?

Answer 1

Answer:

Energy-

and it can be added to an atom to cause a non-valence electron in the atom to temporarily become a valence electron

Answer 2

Answer:

What can be added to an atom to cause a nonvalence electron in the atom to temporarily become a valence electron is energy.

Explanation:

The normal state of the atoms, where all the electrons are occupying the lowest possible energy level, is called ground state.

The valence electrons are the electrons that occupy the outermost shell, this is the electrons in the highest main energy level (principal quantum number) of the atom.

So, a nonvalence electron occupies an orbital with less energy than what a valence electron does; in consequence, in order to a nonvalence electron jump from its lower energy level to the higher energy level of a valence electron, the former has to absorb (gain) energy.

This new state is called excited state and is temporary: the electron promoted to the higher energy level will emit the excess energy, in the form of light (photons), to come back to the lower energy level and so the atom return to the ground state.