Question

which si unit of length is most commonly used to indicate the radius of an atom? a 1 picometer (pm) b 1 millimeter (mm) c 1 micrometer (μm) d 1 nanometer (nm)

Explanation:

Atomic radii are extremely small. Let's analyze each option:

• \(1\) millimeter (\(1\ mm = 10^{-3}\ m\)) is too large for atomic radius.
• \(1\) micrometer (\(1\ \mu m= 10^{- 6}\ m\)) is also too large.
• \(1\) nanometer (\(1\ nm = 10^{-9}\ m\)) is still relatively large compared to atomic scale.
• \(1\) picometer (\(1\ pm=10^{-12}\ m\)) is the appropriate unit as atomic radii are on the order of \(100\ pm\) (e.g., hydrogen atom radius is about \(37\ pm\)).

Answer:

A. 1 picometer (pm)