How are hydrogen bonds different from covalent and ionic bonds?

1 Answer
May 10, 2014

Hydrogen bonds are intermolecular forces; covalent and ionic bonds are intramolecular forces.


Ionic Bonds

Ionic bonds form when one atom transfers electrons to another atom.

The atom that loses an electron becomes a positive ion. The atom that gains an electron becomes a negative ion.

The electrostatic attraction between these ions is an ionic bond.

The ions in ionic solids are close to each other, so ionic attractions are strong.

Ionic bonds are intramolecular bonds, because the ions exert forces among the ions of the same compound.

Ionic bond strengths (lattice energies) range from 600 kJ/mol to 6000 kJ/mol.

Covalent Bonds

Covalent bonds form when two atoms share electrons.

The covalent bonds are intramolecular bonds because they hold the atoms together in a single molecule.

Covalent bond strengths range from 100 kJ/mol to 1100 kJ/mol.

Hydrogen Bonds

Hydrogen bonds are especially strong intermolecular forces.

They exist when you have a negative #"O"#, #"N"#, or #"F"# atom in one molecule and a positive #"H"# atom attached to an #"O"#, #"N"#, or #"F"# atom in another molecule.

Water is the best-known compound that has hydrogen bonds.

Hydrogen bonds have strengths ranging from 5 kJ/mol to 50 kJ/mol.

In summary, hydrogen bonds are (relatively weak) intermolecular forces, while covalent and ionic bonds are (relatively strong) intramolecular forces.