Nuclear fusion bonds together lighter atoms to form heavier atoms.

Once the universe cooled enough for the electrons and nuclei to form atoms this changed.

This makes electrons and protons stick together to form atoms.

They can later join to form heavier atoms.

When the universe cooled enough, protons and electrons combined to form neutral atoms.

The model, then, claimed to explain how particles linked together to form atoms.

Finally at about 400,000 years after the 'bang', it's cool enough for the nuclei to capture their electrons, forming neutral-charge atoms.

Finally, these atomic nuclei captured electrons to form atoms.

For this reason, electrons are attracted by the protons of atomic nuclei and usually form atoms.

The over-excited particles emit so much light, in fact, that their energies fall to a level at which they can combine to form stable atoms.