# Problem: The diameter of a rubidium atom is 4.95 Å. We will consider two different ways of placing the atoms on a surface. In arrangement (a), all the atoms are lined up with one another. Arrangement (b) is called a close-packed  arrangement because the atoms sit in the "depressions" formed by the previous row of atoms: If extended to three dimensions, which arrangement would lead to a greater density for Rb metal?

###### FREE Expert Solution

The ratio of atoms in arrangement B to arrangement A is:

• Atom A: 4.713 x 1014 atoms
• Atom B: 4.081 x 1014 atoms
###### Problem Details

The diameter of a rubidium atom is 4.95 Å. We will consider two different ways of placing the atoms on a surface. In arrangement (a), all the atoms are lined up with one another. Arrangement (b) is called a close-packed  arrangement because the atoms sit in the "depressions" formed by the previous row of atoms:

If extended to three dimensions, which arrangement would lead to a greater density for Rb metal?