Answer:
Explanation:
An isotope is any of two or more forms of an element where the atoms have the same number of protons, but a different number of neutrons within their nuclei.
As a consequence, atoms for the same isotope will have the same atomic number but a different mass number (atomic weight).
In the figure below we see three isomers of Beryllium.
Mass number = proton + neutron
Proton number = atomic number
Mass number – the total number of protons and neutrons in an atomic nucleus.
Atomic mass – the number, equal to the number of protons in an atom that determines its chemical properties. Symbol: Z
