An element crystallises in bcc structure the edge length of its unit cell is 288 pm . The density of the crystal is `7.2 g cm^(-3)` . What is the atomic mass of the element ?

Explanation

Given, Z for bcc = 2 , a = 288 pm
` = 2 .88 xx 10^(-10) cm` .
` rho = 7.2 g cm^(-3), N_(A) = 6.023 xx 10^(23)`
Applying the formula .
` M = (rho xx a^(3) xx N_(A))/(Z)`
` = (7.2 xx (2.88xx 10^(-10))^(3) xx 6.023 xx 10^(23))/(2)`
` = 51.79 g mol^(-1)` .