Gold crystallizes in a face-centered cubic unit cell that has an edge length of 4.078 . The atom in the center

Calculate the density of gold metal.

atoms per unit cell is 8*1/8 +6*1/2 = 4

(4.078 E-8 cm)^3= 67.82 E-24 cm3 = vol of unit cell

vol of one atom is 1/4 above = 16.95 E-24 cm3

1 mole = 6.023 E23 atoms = 197.0 g

197.0 g /6.023 E23 atoms * 1atom/16.95 E-24 = 197.0g /10.21 cm3 = 19.30 g/cm3


agrees well with "chemical elements"

Name: Gold
Symbol: Au
Atomic Number: 79
Atomic Mass: 196.96655 amu
Melting Point: 1064.43 °C (1337.5801 K, 1947.9741 °F)
Boiling Point: 2807.0 °C (3080.15 K, 5084.6 °F)
Number of Protons/Electrons: 79
Number of Neutrons: 118
Classification: Transition Metal
Crystal Structure: Cubic
Density @ 293 K: 19.32 g/cm3 <------------------------------------
Color: Gold