Chemistry of Living Organisms
A. Matter
- anything that takes up space has mass
- all living and nonliving things are made of matter
- matter is made up of particles called ATOMS
B. Atoms
- the basic building block of matter
- composed of three main particles
> protons - positive charge found in nucleus
> neutrons - neutral charge found in nucleus
> electron - negative charge found outside the nucleus rotating in paths or ORBITALS around the nucleus
- atoms join together to make a MOLECULE
C. Molecules
- when two or more atoms join together they form a molecule
- when molecules join together they can be either an ELEMENT or a COMPOUND
D. Elements
- a pure substance that cannot be broken down into simpler substances
- represented by a chemical symbol
1. carbon = C
2. calcium = Ca
3. iron = Fe (from the latin root word ferrum)
4. hydrogen = H
- when 2 or more different elements join together they form a COMPOUND
E. Compounds
- compounds are not pure, they are made of two or more different elements
- a molecule is the smallest particle of a compound (a glass of water has many molecules of water). You can also have a molecule of an element, if more than one atom of that element are joined together. (this happens with oxygen, for example. Oxygen in its natural state is 2 atoms of oxygen joined together, or O2. O2 is one molecule of oxygen.)
- compounds are represented by the chemical symbols of elements (H2O)
- this representation is called a CHEMICAL FORMULA
F. Chemical Formulas
- H2O = 1 molecule of water
>H2 = 2 atoms of hydrogen
>O = 1 atom of oxygen
- CO2 = 1 molecule of carbon dioxide
- C = 1 atom of carbon
- O2 = 2 atoms of oxygen
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