Question 181205
In a crystal of Platinum , the centers of the atoms are 2.8 Angstroms apart along the direction of the closest packing . How many atoms would lie on a one-centimeter line in this direction .
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1 Angstrom = 10^-10 meters = 0.1 nanometer (Angstroms aren't used much, no longer common)
2.8 A = 0.28 nanometers = 0.28*10^-9 meters
1 cm = 0.01 meter
0.01 meters/0.28*10-9 meters = 1/28 *10^9 atoms
= 100/28*10^7 atoms
= 3.57*10^7 atoms