An atom in an excited state a. has more energy than it does in the ground state b. has one more electron than it does in the ground state c. is more stable than it is in the ground state d. has less energy than it does in the ground state

The answer should be A, has more energy than it does in the ground state. De-excitation is removing electrons, so excitation would be adding more in to make it more stable. The ground state is what is considerd stable.

ANSWER: A

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.