Why do two atoms combine?

Answer 1

Atoms combine chemically if the combined molecule has a lower overall energy than he individual atoms. In the same way that a ball rolls downhill to find the lowest point, atoms will combine (given the opportnunity) in such a way as to achieve the lowest overall energy. (As it's the electrons that take part in bonding, it's the overall energy of the electorns that matters for this, not the energy tied up in the nuclei.) And in the same way that a rolling ball may not reach the lowest level because of humps, bums and upslopes, there may be no way for a bunch of atoms to reach their lowest energy configuration without having to pass through a higher-energy intermediate state. So ammonia (NH3) has a much lower energy than hydrogen and nitrogen, but is hard to make because the atoms have to be "pushed uphill" first. It takes high pressures and temperatures to get the reaction to occur. Hydrogen and chlorine on the other hand have no such problem and need no encouragement to form hydrogen chloride.

Answer 2

elements combine with elements because they want to become the stablest form they can be (which is the noble gases) so they gain/lose electrons to get to being like a noble gas then they are stable and do not react

Answer 3

Two atoms combine to form a stable molecule by sharing or transferring electrons in order to achieve a full outer electron shell. This allows the atoms to lower their overall energy and become more stable by following the octet rule.

Answer 4

Atoms combine with other atoms in order to become stable, which for most atoms means having 8 valence electrons.

Answer 5

atoms of elements combine to form molecules of compounds.

Answer 6

Two atoms combine either to exchange one or more electrons or to share one or more electrons, in order to obtain a more stable electron configuration for both atoms.