Positive and negative charges in chemistry


What happens in an atom that causes it to be negative/positive, why do they repel each other, and why does this even happen in the first place?

In: Chemistry

Positive and negative don’t repel each other. One of the defining features of electric charge is that positive attracts to negative, but repels other positive charges.

What happens to make these charges is that atoms are made of positive and negative charges, in the form of protons (positive) and electrons (negative). They always have those charges. When you have an equal number of protons and electrons, you have a neutral atom. However, electrons can leave, and more electrons can be added. When these happen, the entire atom becomes charged.

Atoms are made up of electrons, protons, and neutrons. Neutrons have no charge. Forget about them.

Each proton has 1 unit of positive charge. Each electron has 1 unit of negative charge.

If the number of protons and electrons is equal, the atom is neutral (opposite charges cancel each other out).

If the atom gains or loses an electron, it will either become positively charged (if it loses an electron) or negatively charged (if it gains an electron). This can happen lots of ways. Different chemical processes result in electrons being gained or lost. You can even physically knock electrons out of atoms (rubbing your feet over a carpet to gain an electrical charge to shock someone, for example).

Positive and negative charges in chemistry are really just positive and negative charges in physics. To explain why protons are positive and electrons are negative requires some light quantum physics, but it doesn’t ultimately have a satisfying answer.

The law that opposite charges attract and similar charges repel is just a law of the universe, and one of the four “interactions” that make up reality itself. Without that rule, most if not all of what we understand about matter doesn’t actually make sense.

The tl;dr is that nothing “happens” to make certain particles positive versus negative. They just are.

Though, I think this is a bit complex for a 5-year old 😛