QUANTUM MECHANICAL MODEL.pptx

educational

1. QUANTUM MECHANICAL MODEL

2. Lesson Objectives a . understand the development of atomic models; b.identify the energy levels, sublevels and atomic orbitals in an atom; and c. write the electron configuration of the elements.

3. MOST ESSENTIAL LEARNING COMPETENCIES Explain how the Quantum Mechanical Model of the atom describes the energies and positions of the electrons.

4. ENABLING COMPETENCIES Describe how Bohr model of the atom improved Rutherford`s atomic model.

5. BOHR’S ATOMIC MODEL - describe s the atom as a solar system, where he considered electrons as the particles moving around the nucleus with the specific circular paths called orbits.

6. WAVE MECHANICAL MODEL OF AN ATOM

7. De Broglie proposed that the electrons (which thought as a particle) could also be taught as a wave. LOUIS VICTOR DE BROGLIE

8. Erwin Schr o dinger - used the idea of De Broglie to develop a mathematical equation to describe the probable location of an electron around the nucleus.

9. Heisenberg discovered that for every small particle like the electron, its location cannot be exactly known. This is called the Uncertainty Principle. Werner Heisenberg

10. QUANTUM NUMBERS, ORBITALS AND ENERGY LEVELS

11. Quantum Number ORBITALS are three-dimensional description of the most likely location of an atom. -is a value that is used when describing the energy levels available to atoms and molecules.

12. ENERGY LEVEL -a fixed amount of energy that a system described by quantum mechanics, such as a molecule, atom, electron, or nucleus, can have.

13. THE FOUR QUANTUM NUMBERS (n) l m l m s

14. PRINCIPAL QUANTUM NUMBER -describes the energy level of an electron inside an atom. (n) = 1, 2, 3, 4 and so on.

15. PRINCIPAL QUANTUM NUMBER -each principal energy level is also known as an electron shell. -a collection of atomic orbitals with the same principal quantum number value.

16. ANGULAR MOMENTUM QUANTUM NUMBER - this number describes the shape of the sublevel within an energy level. - represented by l

17. ORBITALS s (sharp) l =0 p (principal) l =1 d (diffuse) l =2 f (fundamental) l =3

18. Relationship between (n) and ( l ) l < n-1 n=2 l =0,1 n=1 l =0 n=3 l =0,1,2

19. MAGNETIC QUANTUM NUMBER - number that describes the orbital within the sublevel. -represented by the symbol (m l ). l m l 1 -1,0,1 2 -2,-1,0,1,2 3 -3,-2,-1,0,1,2,3

20. -indicates the direction the electron is spinning. -represented by the symbol m s. ELECTRON SPIN m s = ±½

21. ELECTRON CONFIGURATION - is a way of distributing the electrons of the atom among the orbitals of the atom.

22. RULES IN ELECTRON CONFIGURATION

23. PAULI’S EXCLUSION PRINCIPLE -states that electrons occupying the same orbitals must have opposite spin.

24. AUFBAU PRINCIPLE -the available atomic orbitals with the lowest energy levels are occupied before those with higher energy levels .

25. HUND’S PRINCIPLE OF MULTIPLICITY -when electrons enter a sublevel with more than one orbital, they will spread out to the available orbitals with the same spin before pairing.

26. EXAMPLES

27. 1s 2 2s 1 s=2 electrons p=6 electrons d= 10 electrons f=14 electrons

28. 1s 2 2s 2 2p 3

29. 4 Be 1s 2 2s 2

30. 10 Ne 1s 2 2s 2 2p 6

31. 1s 2 2s 2 2p 5

32. 19 K 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1

33. 11 Na 1s 2 2s 2 2p 6 3s 1

34. 29 Cu 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 9

35. 14 Si 1s 2 2s 2 2p 6 3s 2 3p 2

36. 36 Kr 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6

37. 26 Fe 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6

38. 22 Ti 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 2