1. For simplicity, suppose a grain of sand is a cube that is 0.2 millimeter on each edge. About how many grains of sand packed tightly together would it take to
make a beach 300 meters long, 25 meters wide, and 5 meters deep?

What are the first two quantum numbers for the electrons located in subshell 4d? what are the first three quantum numbers for the electrons located in subshell 2s? how many electrons can be held in a sublevel l = 3? how many electrons can be held in the energy level n = 4? how many electrons in an atom can share the quantum numbers n = 4 and l = 3?