The Chemistry of the Atomic Bomb (Level 1)

Level 1: Elements and Isotopes

In Year 1, you would have learnt that an element is a substance that cannot be broken down into simpler substances by chemical methods and that an atom is the smallest unit of an element.

Atoms consist of subatomic particles: protons, neutrons and electrons. Protons and neutrons are contained in a nucleus and electrons surround the nucleus. In normal atoms, there are the same number of protons and electrons. The term 'nucleons' refer to both protons and neutrons. The table below compares these 3 subatomic particles.

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These elements are arranged in a periodic table according to their proton number. Isotopes are atoms of the same element that have the same number of protons but different number of neutrons and are commonly expressed as [element]-[nucleon number]. For example, Carbon-12 means that carbon has 12 nucleons, that means a total of 12 protons and neutrons. As all isotopes of carbon have the same number of 6 protons, Carbon-12 has 6 neutrons. 

Q: Do ALL elements have naturally-occurring Isotopes?

Ans: A few elements do not have isotopes. Examples include Beryllium, Fluorine and Sodium.

Q: Do all elements have the SAME number of Isotopes?

Ans: NO. Hydrogen has 3 naturally-occurring isotopes: protium (hydrogen-1), deuterium (hydrogen-2), and tritium (hydrogen-3). In contrast, Tin has 10 naturally-occurring isotopes.