Ligações Covalentes

Covalent bonds share valence electrons, which fill each atom’s outer shell and create one stable molecule; in this case, with a single bond.

The number of covalent bonds can increase depending on how many electrons are shared. For example, when two oxygen atoms, each with six valence electrons, share two pairs of electrons, a double bond forms.

These bonds are nonpolar covalent because the electrons are shared evenly between the atoms. The atoms have the same attraction for the electrons in the covalent bond, meaning they have the same electronegativity.

If two different elements have similar electronegativity, such as carbon and hydrogen, they share electrons relatively equally, forming a nonpolar covalent bonds.

The more strongly an atom attracts the electrons in a covalent bond, the more electronegative the atom.

When two different elements with very different electronegativity bond together, they share electrons unequally, forming a polar covalent bond.

For example, water has one oxygen atom and two hydrogen atoms. The oxygen atom holds the negatively charged electrons most of the time, giving it a partial negative charge.

This situation leaves the hydrogen atoms with a partial positive charge, which makes the compound polar.

These covalent bonds usually form between nonmetals such as carbon, hydrogen, nitrogen, oxygen, and chlorine.