An electron jumps from energy level 1 to energy level 2 by absorbing a photon of energy 8 eV. What is the most likely energy of the photon that will be emitted by the electron when it moves back down to energy level 1? A. 2 eV
B. 4 eV
C. 8 eV
D. 12 eV

C. 8 eV

Explanation:

In atoms, the energy of each level is quantised. That is one of the reasons why an electron can not exist between energy levels. Thus, when the electron absorbs energy of 8 ev, it get excited and jumps to energy level 2 which has the current value of energy of the electron.

Thus for the electron to move back to its initial energy level, it must emit the exact energy absorbed for its excitation. Therefore, the likely energy of the photon that will be emitted is 8 ev. This would make the electron to have energy that would make it to exist on energy level 1.

what are the choices?

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.