Isotopes – revision notes

Isotopes are atoms of the same element, with different numbers of neutrons. The nuclei of different isotopes of the same element have the same number of protons but different numbers of neutrons. Most elements have isotopes. For example, calcium has six, magnesium has three, hydrogen has three, iron has four, and chlorine has two isotopes. […]


All atoms are made of three basic particles: the proton, electron, and neutron. Let’s see how these were identified or discovered. We will also answer a set of related questions on atoms, protons, neutrons and electrons. How were electrons identified? The first strong evidence that something existed smaller than an atom came in 1897. English […]

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