Two different isotopes of the element selenium will have the same number of
A) protons but a different number of neutrons.
B) protons but a different number of electrons.
C) protons and neutrons, but they are arranged differently in the nucleus.
D) neutrons but a different number of protons.

Question

Quizplus · Accepted Answer

Isotopes of an element have the same number of protons (which defines the element) but differ in the number of neutrons in their nuclei. This difference in neutron number does not affect the chemical properties of the element, which are primarily determined by the number of protons (and hence electrons in a neutral atom).

Two Different Isotopes of the Element Selenium Will Have the Same