When tow valence electrons are shared by two atoms, it is called this type of bond. when four valence electrons are shared by two atoms, it is called this type of bond. a less common type, this is a weak bond between hydrogen and another atom, usually oxygen, fluorine, or nitrogen.
When electrons are shared between two atoms, they make a bond called a covalent bond. Because two atoms are sharing one pair of electrons, this covalent bond is called a single bond.
Double bonds occur when four electrons are shared between the two atoms and consist of one sigma bond and one pi bond. Triple bonds occur when six electrons are shared between the two atoms and consist of one sigma bond and two pi bonds (see later concept for more info about pi and sigma bonds).
Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability.
Why do electrons come in pairs?
It is due to the fact that even though electrons have negative charge they are bound to the nucleus by the attraction force from the nucleus and thus they have to somehow be around the nucleus and at the same time be in the lowest possible energy situation.
What is holding atoms together?
Atoms can be held together by chemical bonds. When atoms form bonds, they can achieve a stable electron arrangement. To achieve a stable electron arrangement atoms can lose, gain or share electrons. There are different types of bonds that hold atoms together.