Metric has only seven fundamental units:
•mass (kilogram, kg)
•length (meter, m)
•time (second, s)
•temperature (Kelvin, K)
•chemical amount (mole, mol)
•electrical current (Ampere, A)
•luminosity (candela, cd)
All other metric units are just combinations of these seven units, and in General Chemistry we only need to use the first five. This is the elegance and simplicity of the metric system.
For example, the metric unit of energy is the Joule (J). The Joule is a combination of kg, m, and s:
Prefixes / Powers of 10
Metric prefixes represent powers of 10.
| Prefix | Abbr. | Meaning | Example 1 | Example 2 |
| kilo- | k | 1000 | 1 kg = 1000 g | 1 g = 0.001 kg |
| centi- | c | 0.01 | 1 cm = 0.01 m | 1 m = 100 cm |
| milli- | m | 0.001 | 1 mL = 0.001 L | 1 L = 1000 mL |
| micro- | μ | 0.000 001 | 1 μg = 0.000 001 g | 1 g = 1,000,000 μg |