C. if the proton number increases while the number of energy levels remains constant,
what happens to the attractive force between the nucleus and the electrons ?

Here, we are required to determine what happens to the attractive force between the nucleus and the electrons if the proton number increases while the number of energy levels remains constant.

By the primary law of electric charges:

Unlike charges attract while like charges repel.

The proton number refers to the number of protons in the nucleus of an atom.

According to the question; the proton number increases while the number of energy levels remains constant.

Since the number of energy levels remains constant, no new orbitals are formed and consequently the distance between the nucleus and the electrons remains constant.

However, the presence of more protons due to the increase in the proton number leads to higher electrical force of attraction between the positively charged nucleus and the electrons.

Ultimately, the attractive force between the nucleus and the electrons increases if the proton number increases while the number of energy levels remains constant.

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1.43 x 10^-11 j the guy commented the awnser just making sure u see it .