Electrons in the Atom

1. Electrons in the Atom

2. Heisenberg Uncertainty Principle • This is the theory that states that it is impossible to determine simultaneously both the position and velocity of an electron or any other particle.

3. Quantum Theory • Schrodinger derived an equation that described energy & position of electrons in atom • Schrodinger along with other scientists laid the foundation for the modern quantum theory, which describes mathematically the wave properties of electrons and other very small particles.

4. Orbitals & Quantum Numbers • Electrons exist around the nucleus in certain regions called atomic orbitals- 3D regions around the nucleus that indicates the probable location of an electron. • Quantum numbersare used to describe atomic orbitals. The quantum numbers are like an address for the electrons.

5. S orbitals • 1 s orbital for every energy level • Spherical shaped • can hold 2 electrons • Called the 1s, 2s, 3s, etc.. orbitals.

6. P orbitals • Start at second energy level • 3 different directions • 3 different shapes • Each can hold 2 electrons

7. P Orbitals

8. D orbitals • Start at third energy level • 5 different shapes • Each can hold 2 electrons

9. F orbitals • Start at fourth energy level • 7 different shapes • 2 electrons per shape

10. F orbitals

11. Summary of Orbitals # of shapes Max electron Starts at energy level s 1 2 1 p 3 6 2 5 10 3 d 7 14 4 f

12. Orbitals do not fill up in a neat order. Energy levels overlap Lowest energy fill first. By Energy Level

13. Electron Configuration • Way electrons are arranged in atoms. • Aufbau principle- electrons occupy the lowest-energy orbital that can receive it. This means electrons enter the lowest energy first.

14. This causes difficulties because of overlap of orbitals of different energies. • Pauli Exclusion Principle- states that no 2 electrons in the same atom can have the same set of four quantum numbers. Basically, at most there are 2 electrons per orbital with different spins.

15. Hund’s Rule- Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron. • This means when electrons occupy orbitals of equal energy they don’t pair up until they have to. • (BUS RULE)

17. Valence Electrons, Lewis Dot Structures,Electron Configuration & Orbital Notation • Get out your periodic table and follow along on the handout