Why is it impossible for an element to have an atomic number of 110.5? (1 point)

Question

Responses

Atoms with atomic numbers greater than 100 are unstable.
Atoms with atomic numbers greater than 100 are unstable.

Atoms of an element all have the same whole number of protons and neutrons.
Atoms of an element all have the same whole number of protons and neutrons.

​Exactly half of the isotopes would need an atomic number of 110, and half would need an atomic number of 111, which is very unlikely.
​Exactly half of the isotopes would need an atomic number of 110, and half would need an atomic number of 111, which is very unlikely.

The atomic number is the number of protons, which is always a whole number.

Answer 1

The correct response is:

The atomic number is the number of protons, which is always a whole number.

Atomic numbers represent the number of protons in the nucleus of an atom, and since protons are discrete particles, the atomic number must always be a whole number. Thus, an atomic number of 110.5 is not possible.