What's an Ion?

An ion is an atom or a group of atoms that carries an electrical charge. This occurs when an atom gains or loses electrons, altering the balance between positively charged protons and negatively charged electrons.

A neutral sodium atom has 11 protons and 11 electrons, resulting in no net charge. If sodium loses one electron, it retains 11 protons but now only has 10 electrons. This imbalance leads to a net positive charge of +1, forming a sodium ion (Na+), which is called a cation (a positively charged ion).

A neutral oxygen atom has 8 protons and 8 electrons. Oxygen commonly gains two electrons, resulting in 8 protons and 10 electrons. This gives it a net negative charge of -2, forming an oxygen ion (O2-), which is called an anion (a negatively charged ion).

An ion is a charged atom or group of atoms. A neutral atom has no charge. A cation is a positive ion, and an anion is a negative ion. A mnemonic for remembering anions is 'a negative ion', and for cations, 'cats have paws' (paws sounds like 'positive').

A polyatomic ion is a group of atoms bonded together that collectively carry an electrical charge. 'Poly' means many, indicating multiple atoms forming a single ion. These will be discussed in more detail in future videos.

An ion is an atom or group of atoms with a charge, created when the number of protons and electrons doesn't balance. More protons than electrons result in a positively charged cation, while more electrons than protons result in a negatively charged anion.