Question

1. what is an energy level?

the region outside the nucleus where a proton is likely to be moving
the region outside the nucleus where a neutron is likely to be moving
the region inside the nucleus where an electron is located
the region outside the nucleus where an electron is likely to be moving

Explanation:

• Protons and neutrons are located in the nucleus, so options 1 and 2 are incorrect.
• Electrons are outside the nucleus, not inside, so option 3 is incorrect.
• Energy levels are the regions outside the nucleus where electrons are likely to be moving.

Answer:

the region outside the nucleus where an electron is likely to be moving