what are electrons made of

Electrons are leptons. Previous answer submitted was "electrons are made up of quarks" They most certainly are not! Protons and neutrons come together in the center of the atom to form the nucleus.

The electrons in orbitals closest to the nucleus are held most tightly; those in the outermost orbitals are shielded by intervening electrons and are the most loosely held by the nucleus. These electrons are bound to the nucleus by an electromagnetic force.

An atom is made up of three particles called protons, neutrons and electrons. As the electrons move about within this structure, they form a diffuse cloud of negative charge that occupies nearly the entire volume of the atom. A quark is a tiny particle which makes up protons and neutrons.Atoms are made of protons, neutrons and electrons. Electrons orbit the nucleus.

It was once thought that all three of those were fundamental particles, which cannot be broken up into anything smaller.After the invention of the particle accelerator, it was discovered that electrons are fundamental particles, but neutrons and protons are not. An atom is the most basic form of matter and can not be broken down any further.