Atoms are the building block of every matter.<br />Atom made up of electron, Protons and neutrons.<br />Electron always presents in orbitals.<br />these Orbitals then further divide in to sub orbitals which we call s,p,d,f suborbitals.<br />orbitals denote as K,L,M,N,O,P,Q <br />so when we want to say that electron is in 1st orbital we say like electron is in K orbital and represent it like n =1 (K orbital).
