What are some examples of polar and non-polar substances?

Examples of polar substances include:

- Water (H2O)

- Ammonia (NH3)

- Hydrogen Sulfide (H2S)

Examples of non-polar substances:

- Methane (CH4)

- Carbon dioxide (CO2)

- Diatomic gases, such as oxygen gas (O2), hydrogen gas (H2), or nitrogen gas (N2)

Polar substances are covalently bonded substances that contain partially positive and negative charges. The charges are a result of electronegativity differences is the likelihood that an atom will attract a pair of bonded electrons. The range of electronegativity differences is approximately 0.7 to 4.0. Some periodic tables contain electronegativity values of each atom. The electronegativity difference between two atoms forming a bond can be used to determine the type of bond that will be formed between the two atoms, as identified below.

- Electronegativity differences less than 0.5 = nonpolar covalent

- Electronegativity of 0.5 – 1.6 = polar covalent

- Electronegativity difference of 2.0 or more = ionic bond

Please note that if the electronegativity difference between two atoms falls between 0.5 and 1.6, but there is symmetry within the compound, then that compound will not display polarity. This is the reason why carbon dioxide (CO2) is not considered to be polar.