Isotopes of lithium

Isotopes are different forms of the same element. For example, there are three different isotopes of the element lithium. All three isotopes look and act the same as each other, but they are slightly different. For example, one isotope of lithium may have 3 particles in its nucleus and another might have 4 particles. Even though the number of particles in the nucleus is different, it's still the same element - lithium.