Chemistry · Atoms & ions

Inside an Atom.

Every atom is a tiny nucleus with electrons arranged in shells around it. How those electrons are arranged explains the shape of the periodic table, and why atoms turn into ions.

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Key words

NucleusThe tiny centre of an atom, made of protons and neutrons

Proton · neutron · electronCharge +1, in the nucleus · no charge, in the nucleus · charge −1, in shells around the nucleus

Atomic numberThe number of protons. In a neutral atom it is also the number of electrons

Electron arrangementHow many electrons are in each shell, from the inside out, e.g. sodium 2, 8, 1

Valence electronsThe electrons in the outer (valence) shell. Same group, same number of valence electrons

IonA charged particle made when an atom loses electrons (positive ion) or gains electrons (negative ion), usually to get a full valence shell

Where this leads: positive metal ions make up the grid in Inside a Metal, and positive and negative ions together make the ionic compounds in the Precipitate Lab.

Narration voice: Max, generated with ElevenLabs.