How to calculate no. of orbitals in an atom if atomic no. is given?

Answer 1

To determine the number of atomic orbitals from the atomic number, write out the electron configuration of the atom. For example let's use the atom carbon. Carbon's atomic number is 6. It's electron configuration is 1s2 2s2 2p2. The orbitals are represented by the letters, so this means that a carbon atom has 5 atomic orbitals: 2 s orbitals (one in the 1st shell and one in the 2nd shell) and 3 p orbitals (remember that there are always 3 p orbitals of the same energy).