While scientists sometimes conceptualize electrons spinning around an atom's nucleus in a defined shell, they actually fly around the nucleus at various distances; this view of the carbon atom can be seen here in two electron cloud figures (bottom), showing the electrons in a single blob (the so-called s-orbital) and in a two-lobed blob or cloud (the p-orbital). It can link to itself, forming long, resilient chains called polymers.

It can also bond with up to four other atoms because of its electron arrangement.

Carbon has two electron shells, with the first holding two electrons and the second holding four out of a possible eight spaces.

When atoms bond, they share electrons in their outermost shell.

Carbon has four empty spaces in its outer shell, enabling it to bond to four other atoms.

Arrange carbon atoms in one way, and they become soft, pliable graphite. — the atoms form diamond, one of the hardest materials in the world.

Carbon is also the key ingredient for most life on Earth; the pigment that made the first tattoos; and the basis for technological marvels such as graphene, which is a material stronger than steel and more flexible than rubber.

[See Periodic Table of the Elements] Carbon occurs naturally as carbon-12, which makes up almost 99 percent of the carbon in the universe; carbon-13, which makes up about 1 percent; and carbon-14, which makes up a minuscule amount of overall carbon but is very important in dating organic objects.

Just the facts Carbon: From stars to life As the sixth-most abundant element in the universe, carbon forms in the belly of stars in a reaction called the triple-alpha process, according to the Swinburne Center for Astrophysics and Supercomputing.

In older stars that have burned most of their hydrogen, leftover helium accumulates.

Each helium nucleus has two protons and two neutrons.