Question

A compound is formed by two elements A and B. The element B forms a cubic close-packed structure and atoms of A occupy `1/3` of the tetrahedral voids. If the formula of the compound is A_xB_y then the value x + y is in the option:

Options

• 4

• 3

• 2

• 5

Answer 1

5

Explanation:

A: `1/3` of the tetrahedral voids:

Z_A = `1/3 xx 8`

= `8/3`

B: Cubic close-packed:

Z_B = 4

= `8/3 : 4`

= `2/3 : 1`

= 2 : 3

Simplest formula	A2	B3
	↓	↓
	x	y

x + y = 5vv