Water Structure


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•  Water molecules are polar and hydrogen bonds form between them

Water is made up of two hydrogen atoms covalently bonded to an oxygen atom (molecular formula = H2O)

While this covalent bonding involves the sharing of electrons, they are not shared equally between the atoms

  • Oxygen (due to having a higher electronegativity) attracts the electrons more strongly 
  • The shared electrons orbit closer to the oxygen atom than the hydrogen atoms resulting in polarity

water structure

Water is described as being polar because it has a slight charge difference across the different poles of the molecule

  • The oxygen atom is slightly negative (δ) while the hydrogen atoms are slightly positive (δ+)

This charge difference across the molecule (dipole) allows water to form weak associations with other polar molecules 

  • The slightly negative poles (δ) will attract the slightly positive poles (δ+) of other molecules, and vice versa

When a 
δ+ hydrogen atom is attracted to a δ fluorine, oxygen or nitrogen atom of another molecule, it forms a hydrogen bond

  • Hydrogen bonds are relatively stronger than other polar associations due to the high electronegativity of F, O and N