Atom Diagram Labeled – 7 Parts of a Carbon Atom

All 7 parts on the diagram

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Start here: 6 main parts 6

Nucleus The tiny center of the atom, made of protons and neutrons. It holds almost all the atom's mass.
Proton A positively charged particle in the nucleus; carbon has 6.
Neutron A particle with no charge in the nucleus. This carbon atom has 6.
Electron (core electron) A tiny negatively charged particle. The two in the inner shell are core electrons.
Electron shell (energy level) A level at a fixed distance from the nucleus that holds electrons. The first holds at most two.
Valence electron An electron in the outermost shell; these take part in bonding. Carbon has 4.

Other 1

Valence shell (outer shell) The outermost shell that holds electrons.

How this list was compiled: Read 2026-09-26. (1) OpenStax Chemistry 2e, 2.3 Atomic Structure and Symbolism, https://openstax.org/books/chemistry-2e/pages/2-3-atomic-structure-and-symbolism : a very small nucleus of positively charged protons and uncharged neutrons, surrounded by a much larger volume holding negatively charged electrons; the nucleus holds most of the mass and is about 100,000 times smaller across than the atom. (2) OpenStax Chemistry 2e, 6.4 Electronic Structure of Atoms, https://openstax.org/books/chemistry-2e/pages/6-4-electronic-structure-of-atoms-electron-configurations : shells; electrons in the outermost shell are valence electrons, those in inner shells are core electrons. (3) Wikipedia, Bohr model, https://en.wikipedia.org/wiki/Bohr_model (electrons in shells or energy levels round the nucleus) and Valence electron, https://en.wikipedia.org/wiki/Valence_electron (outer-shell electrons take part in bonding). Licence: own work

The drawing: Drawn for this site by script, 2026-09-26. Own work, nothing traced. Licence: own work

How it works

This atom diagram labeled part by part shows a carbon atom in the shell model: 6 protons and 6 neutrons in the nucleus, 2 electrons in the first shell and 4 in the outer shell.

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The nucleus

The nucleus is tiny but holds almost all of the atom's mass. It is made of protons, which carry a positive charge, and neutrons, which carry none. The number of protons decides the element: carbon always has 6.

The electrons

Negatively charged electrons fill the space round the nucleus, in shells at set distances. The inner electrons are core electrons. Those in the outermost shell, the valence shell, are valence electrons, and they take part in bonding.

Not to scale: if this nucleus were drawn to match the atom, it would be far too small to see, about 100,000 times smaller across.

Questions and answers

What are the three particles in an atom?

Protons and neutrons in the nucleus, and electrons round it. Protons are positive, electrons negative, and neutrons have no charge.

What is a valence electron?

An electron in the atom's outermost shell. Valence electrons are the ones that take part in chemical bonds; carbon has four, so it can form four bonds.

Why is the nucleus drawn so big?

So you can see it. A real nucleus is about 100,000 times smaller across than the atom, so the atom is almost all empty space round it.