Question

The Cu metal crystallises into fcc lattice with a unit cell edge length of 361 pm. The radius of Cu atom is:

• A. 157 pm
• B. 181 pm
• C. 127 pm
• D. 108 pm

Answer 1

The Correct Option is C

For a face-centered cubic (fcc) lattice, the relationship between the edge length (a) and the atomic radius (r) is defined by:

\(4r = \sqrt 2 a\)

Where:

• r represents the atomic radius.
• a denotes the edge length.

Given an edge length (a) of 361 pm, the atomic radius (r) can be computed as follows:

\(4r = \sqrt 2 \times 361\) pm

\(4r = 1.414 \times 361\) pm

\(4r = 510.454\) pm

\(r = \frac {510.454}{4}\)

\(r ≈ 127.6\) pm

Consequently, the radius of the Cu atom is approximately \(127\) pm.

The correct response is (A): \(127\) pm