An atom of gold has a diameter of 0.000,000,000,144 m. To write this number in standard form:
Make sure you know how to input power of 10 on your calculator.
Here are some typical atomic diameters:
|Gold||1.44 × 10-10|
|Iron||1.26 × 10-10|
|Copper||1.28 × 10-10|
The diameters are slightly different, but are all about 10-10 m. The size of these atoms is said to have an order of magnitude of 10-10.
To find the order of magnitude estimate, always round to the nearest power of 10.
An atom of oxygen has a diameter of 7.4 x 10-11 m. Give an order of magnitude estimate of the size of an oxygen atom.
7.4 rounds up to 10
10 × 10-11
= 1.0 × 10-10 m
The order of magnitude estimate for an oxygen atom is 10-10.
A dodecane molecule contains a chain of 12 carbon atoms. Each atom has an order of magnitude of 10-10. Give an order of magnitude estimate for the length of a molecule of dodecane.
12 × 10-10
= 1.2 × 10-9 m
The order of magnitude estimate for the size of a molecule of dodecane is 10-9.