Question

when atoms of the same element have different numbers of neutrons, what are they called

Answer 1

Isotopes.

Answer 2

The notation for an isotope of element \(E\) of atomic number \(Z\),
with \(N\) neutrons. And hence \(A = Z+N\) nucleons is;
\[^{A}_{Z}{\text E}_N^{~}\]
___________
for example

Carbon always has 6 protons,
but the number neutrons varies,
the isotopes of carbon include:

carbon-12; \(^{12}_{6}{\text C}_6^{~}\)

carbon-13; \(^{13}_{6}{\text C}_7^{~}\)
&
carbon-14; \(^{14}_{6}{\text C}_8^{~}\)

Answer 3

ISOTOPES