There are three natural isotopes.
argon's atomic number is 18
Isotopes. They differ in the number of neutrons in the nucleus.
Isotopes differ by the number of protons.
Argon is very unreactive as it is a noble gas. Its common oxidation number is zero.
Argon atoms have 18 protons which is similar to the number of electrons.
The atomic number is the same for the isotopes of a chemical element.
Isotopes of the same element have the same number of protons (atomic number) but differ in number of neutrons (hence atomic masses).
Ar
Isotopes have a different number of neutrons.
Isotopes have different number of neutrons.
lithium has 7 isotopes
Different elements with same number of neutrons are known as isotones.