# Question #d72b2

Nov 12, 2016

The most common unit for the atomic radius is the picometre (pm).

#### Explanation:

$\text{1 pm" = 10^"-12"color(white)(l) "m}$

That unit is chosen because it gives easily visualized numbers.

For example, the atomic radius of He is 31 pm, and that of caesium is 265 pm.

Here's how they compare in a chart.

(From saylordotorg.github.io)