Atoms, Elements, Molecules, Compouds

October 11 & 12, 2012

Atoms, Elements, Molecules, Compounds

ATOMS are the basic building blocks of matter.

Atoms are composed of particles called protons, electrons and neutrons.

    Protons carry a positive electrical charge, electrons carry a negative electrical charge  
    and neutrons carry no electrical charge at all. The protons and neutrons cluster together
    in the central part of the atom, called the
nucleus, and the electrons 'orbit' the nucleus.

An ELEMENT is a pure substance that cannot be separated into simpler
      substance by physical or chemical means.

  A MOLECULE is formed when two or more atoms join together chemically. (they can have 2 of the same elements)
  A COMPOUND is a molecule that contains at least two different elements.
  All compounds are molecules but not all molecules are compounds.
  Molecular hydrogen (H2), molecular oxygen (O2) and molecular nitrogen (N2) are not compounds because each is composed of a single element.
  Water (H2O), carbon dioxide (CO2) and methane (CH4) are compounds because each is made from more than one elements.

What Elements are we made up of?
Most of the human body is made up of water, H2O.
Most of a human body's mass is oxygen.
Carbon, the basic unit for organic  molecules, comes in second.
99% of the mass of the human body is made up of just six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus.
How do atoms combine to make compounds? Chemical Bonding
Chemical Bonds, Chemical Bonds, Chemical Bonds!

Click here to see the powerpoint.


  • Inorganic Compounds: Do not contain carbon (except carbon dioxide)
                                  They are mineral in nature.
  • Organic compounds: Contain significant amounts of carbon.
                                  They are biological in nature (bio=living
                                 Click here to for Compounds Class Worksheet

    Four types of organic compounds are important in living systems
    .Carbohydrates, Lipids, Proteins & Nucleic acids 
    Click Here to find out more!



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