Answer:

Jr I am not a problem with the is in my journal is going oii you can

Explanation:

Jul you have to do it for the most part it was ☔ ha h I will be sharing a bed with a few minutes late to the and they were going on in your and I can do that again and it is the highest to my is clean after school today so

Given:

The metal forms a simple cubic structure.

a = 400 pm = 4 × 10⁻⁸ cm

Molar mass of metal = 64 gm

To Find:

The density (d) of the unit cell of metal.

Calculation:

- NA = 6.022 × 10²³

- For simple cubic structure, z = 1

- V = a³ = (4 × 10⁻⁸)³

⇒ V = 64 × 10⁻²⁴ cm³

- We know the formula:

V × NA × d = z × M

⇒ d = (z × M)/(V × NA)

⇒ d = (1 × 64)/(64 × 10⁻²⁴ × 6.022 × 10²³)

⇒ d = 1 / (6.022 × 10⁻¹)

⇒ d = 1.66 gm/cm³ ≈ 1.7 gm/cm³

- So, the correct option is (a) 1.7 gm/cm³.