Which best explains why elements with a completely full outer shell of electrons do not usually bond with other elements to form compounds?

a.
a full outer shell of electrons indicates a stable state, making the formation of compounds unnecessary. the full outer shell was obtained by releasing electrons instead of forming a compound.

b.
these elements have obtained electrons from other elements without bonding to create a full outer shell of electrons, and a stable state.

c.
elements with a completely full outer shell of electrons are in their most stable state. therefore, achieving stability through the formation of compounds is not necessary.

d.
because electrons orbit some atoms in three dimensional space, they move to different orbitals to stabilize the atom, making the formation of compounds unnecessary.
explain.

The best answer is C.

The stability of atoms depends on whether or not their outermost shell is filled with electrons. If the outer shell is filled with electrons, the atom is stable and therefore they do not need to react  with other elements to become stable.

On the other hand, atoms with unfilled outer shells are unstable, and will usually form chemical bonds with other atoms to achieve stability. To achieve stability, atoms will form two types of chemical  bonds called ionic bonds and covalent bonds.

it doesn't. it was imagined up in the middle ages.

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.