How do atoms share electrons in covalent bonding?

In covalent bonding, atoms share electrons to achieve a stable electron configuration, usually a full outer shell.

Covalent bonding is a type of chemical bonding where atoms share electrons to achieve a stable electron configuration. This usually means having a full outer shell, which is the most stable state for an atom. This type of bonding is common between non-metal atoms.

Let's take a simple example of a covalent bond in a molecule of hydrogen (H2). Each hydrogen atom has one electron in its outer shell, but it needs two to be stable. So, the two hydrogen atoms share their electrons, creating a covalent bond. This allows each atom to have a full outer shell, making the molecule stable.

Another example is a molecule of water (H2O). The oxygen atom has six electrons in its outer shell, but it needs eight to be stable. Each hydrogen atom has one electron, so by sharing one electron with each hydrogen atom, the oxygen atom can achieve a full outer shell. At the same time, each hydrogen atom also achieves a full outer shell by sharing an electron with the oxygen atom.

In covalent bonding, the shared electrons are often referred to as 'shared pairs' or 'bonding pairs'. The strength of a covalent bond depends on the number of shared pairs: the more pairs, the stronger the bond. For example, a single covalent bond involves one shared pair of electrons, a double bond involves two shared pairs, and a triple bond involves three shared pairs.

It's important to note that not all atoms can form covalent bonds. The ability to form covalent bonds depends on the atom's electronegativity, which is a measure of how strongly it attracts electrons. Atoms with similar electronegativities are more likely to form covalent bonds.