At room temperature, Polonium (atomic weight 209 gm mol^(-1)) crystallises in a primitive cubic unit cell. If a = 3.36 A^(0), calculate the theoritical density of Polonium..

At room temperature, Polonium (atomic weight 209 gm mol^(-1)) crystall

1.	At room temperature, Polonium (atomic weight 209 gm mol^(-1)) crystallises in a primitive cubic unit cell. If a = 3.36 A^(0), calculate the theoritical density of Polonium..
Answer» Solution : A primitive cubic UNIT cell contains atoms only at the 8 corners with each corner contributing`1//8^(TH)` of an atom . HENCE n = `8 xx (1//8) = 1` . VOLUME `V = a^(3) = (3.36 Å)^(3)` From Eq. 1 `rho = (n M m)/(N_(0) V)` `= ((1) 209 G mol^(-1)))/((6.022 xx 10^(23) mol^(-1)) (3.36 xx 10^(-8) cm)^(3))` `= 9.15 g cm^(-3)`