How do quarks make up protons and neutrons?

Protons and neutrons are not fundamental particles. Instead, they are composite particles known as hadrons, which means they are made of smaller, fundamental particles called quarks. These quarks are bound together by the strong nuclear force.

The Key Quarks

For protons and neutrons, we only need to consider the two "first-generation" quarks:

• Up Quark (u): Has a fractional electric charge of +2/3.
• Down Quark (d): Has a fractional electric charge of -1/3.

Proton (p) Composition

A proton is composed of two Up quarks and one Down quark (uud).

We can calculate its charge by adding the charges of its quarks:

(+2/3) + (+2/3) + (-1/3) = +4/3 - 1/3 = +3/3 = +1

This confirms the +1 charge of a proton.

Neutron (n) Composition

A neutron is composed of one Up quark and two Down quarks (udd).

We can calculate its charge in the same way:

(+2/3) + (-1/3) + (-1/3) = +2/3 - 2/3 = 0

This confirms the 0 (neutral) charge of a neutron.