Introduction to Isotopes

test Isotopes are atoms of the same element with different numbers of neutrons but the same number of protons. For example, different isotopes of the element Carbon can have 6, 7, or 8 neutrons. The number of protons does not change.

Because of the different numbers of neutrons, isotopes also have different mass numbers.

Exercise: Select the two isotopes of Oxygen below.
	A	B	C
	7 protons 8 neutrons Mass Number=15	8 protons 8 neutrons Mass # =16	8 protons 10 neutrons Mass # =18