C5 - Chemicals in the Atmosphere

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The Atmosphere

The earths atmosphere contains many gases

Some of these gases are elements  (oxygen - O2 , Nitorgen - N2, Argon- Ar)  They contain ONLY ONE TYPE OF ATOM

Other gases are compounds (Carbon Dioxide - CO2 ,) They contain MORE THAN ONE TYPE OF ATOM bonded together

There are different amounts of each of thses gases in the atmosphere - 78% Nitrogen, 21% Oxygen, 1% Argon and 0.04% Carbon Dioxide

Most of the gases in the atmosphere are molecular substances

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Molecular Substances

Molecular substances usually exist as small molecules like C02 and H20

The atoms within the molecules are held together by VERY STRONG COVALENT BONDS

However, the FORCES OF ATTRACTION between these molecules are VERY WEAK

Only a tiny bit of energy is needed to overcome the weak forces between the molecules - MOLECULAR SUBSTANCES HAVE LOW MELTING//BOLING POINTS

This means they're usually gases and liquids at room temperature

Pure molecular substances don't conduct electricity because the molecules arent charged - no free electrons or ions

Most non-metals and most compounds formed from non-metals are molecular 

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