The number of sublevels within each energy level

What is a quantum number? The number of sublevels within each energy level. That is; for energy level n=1 there is only 1 sublevel but for n=4 there are 4 sublevel.How are sublevels indicated?Number electrons allowed in each sublevel?What is the sequence for filling the levels with electrons?Be able to write correct outline for electron dot structure.What is ionization energy and what does it relate to?