posted by HELp .
The density of an unknown metal is 8.94 g/cm^3 and its atomic radius is 0.126 nm . It has a face-centered cubic lattice. Find the atomic weight of the unknown metal.
4*radius = sqrt(2)*a
solve for a. I recommend converting radius to cm (from nm).
a is the length of a side of the crystal; therefore, a^3 will be the volume of the cube in cc.
mass of the unit cell = volume x density.
Substitute mass into
mass = 4unitcells*molar mass/6.022 x 10^23. and solve for molar mass.