How many atoms ar in one unit cell of calcium ?

Options

A. `4`
B. `3`
C. `2`
D. `1`

Answer

3

Explanation

Calcium `(Ca)` a soft white metal that tarnishes rapidly in air crystallizes in face centred cubic lattice.
All the metal of Group `10` and `11` possess a face centred also crystallize in a face -centered cubic (fcc) arrangemettn.A face4-centered structure involves the eight points of the corners and six more equivalent points one of the middle of each of the six square faces of the cell.
A metal that cystallizes in this arrangement has `8(1//8)=1` atoms at the corners plus `6(1//2)=3` more in the faces ,for a total of four atoms per unit cell.
In more complicated crystals ,each lattice site amy sepresent several atoms or an entire molecules.