1. CHAPTER 7 Quantum Theory and the Electronic Structure of Atoms Semester 2 / 2013 7.6 Quantum Numbers 7.7 Atomic Orbital 7.8 Electronic configuration (Refer lecture) 7.9 The building-up principle

2. Quantum Numbers Principal Q. No (n) n =1,2,3,4…… Distance of e - from the nucleus n=1K shell n=2L shell n=2M shell n=2N shell... Angular momentum Q.No (l) l=0  n-1 Shape of the “volume” of space that the e - occupies l 012345 Orbitalspdfgh Magnetic Q.No (m l ) m l = -l….0, + l Orientation of the orbital in space Electron Spin Q.No (m s ) m s = +

3. Example : 1 List values of n,l,m l in 2p sub shell 2p n l =1 i.e. n=2, l =1, m l = -1,0,1

4. EXAMPLE 2 TOTAL NUMBER OF ORBITALS ASSOCIATED WITH PRINCIPAL QUANTUM NO “2 ” n=2 l =0 m l =0 l =1 m l =1 m l =2 m l =3 1

5. EXAMPLE 3 List different ways to write four quantum Numbers that designate e - in A as orbital n=4, l=0, m l =0, m s = + n=4, l=0, m l =0, m s = -

6. 7.7 Atomic Orbitals l = 0 (s orbitals) l = 1 (p orbitals)

7. l = 2 (d orbitals)

8. 7.8 Electron Configuration Refer Chapter 2 Lecture notes

9. 7.9 The building-up Principle Aufbau principle : As protons are added one by one to the Nucleus to build up the elements, electrons are similarly add to the atomic orbitals.

10. Example : AtomicSymbolElectron Configuration Number 1 2 3 4 5. 21. 24. 29 H He Li Be B. Sc. Cr. Cu 1s 1 1s 2 [He]2s 1 [He]2s 2 [He]2s 2 2p 1. [Ar]4s 2 3d 1. [Ar]4s 1 3d 5. [Ar]4s 1 3d 10