Copper occurs in nature in the form of two isotopes, cu-63 and cu-65. its correctly recorded atomic mass (weighted average) is 63.5 amu. without doing the math, explain why it is safe to say that cu-63 is more abundant than cu-65.

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?