What is an ion and what is an cation

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?

How is the atomic number of a nucleus changed by alpha decay

What is the oxidation state of an individual bromine atom in nabro3?