Honors Chemistry

1. Honors Chemistry September 16, 2013

2. Preview of Lesson • Where are electrons found around the nucleus? • 4 different shaped orbitals (x-ray diffraction and electron microscopy) • s, p, d, f • Higher energy levels have more shapes • Each orbital can hold 2 e- • Locate the e- 90% of the time • Orbital is also called Subshells

3. Bohr's Model • Model ofelectronsin fixedorbits to explain quantization Figure 6.14 • Transitionsbetweenorbitsemits orabsorbslight 07m07an1

4. Observation of unique line spectra led to Quantum Theory E=hν Fourth Third Second First Nucleus

5. Orbital Diagrams and Electron Configurations • n = Principle quantum number • Describes the energy level the electron occupies (PT) n = 4 n = 3 n = 2 n = 1

6. Orbital Energy Levels • Shape of orbital designated by the letters s, p, d, f Excited states Ground state

7. Shapes of Orbitals • Shape of orbital designated by the letters s, p, d, f • Orbitals have different shapes

8. s Orbital shape The s orbital has a spherical shape centered around the origin of the three axes in space.

9. p orbital shape There are three dumbbell-shaped p orbitals in each energy level above n = 1, each assigned to its own axis (x, y and z) in space.

10. d orbital shapes Things get a bit more complicated with the five d orbitals that are found in the d sublevels beginning with n = 3. To remember the shapes, think of “double dumbells” …and a “dumbell with a donut”!

11. Shape of f orbitals

12. Combination of electron microscopy and x-ray diffraction produced image of orbitals

13. Sets of Orbitals (Subshells) • Depending on the type of orbital, we find that they occur in sets differing in their orientation in space • s - set of 1 • p - set of 3 • d - set of 5 • f - set of 7 • Label P.T.

14. Sizes of orbitals • Size depends on the value of n • Orbitals with the same n are about the same size

15. Check for understanding • What is the principal quantum number for Ar? • What are the subshells? • How many sets of electrons are found in each subshell?

16. The firstten elements 1s1 1s2 1s2 2s1 1s2 2s2 1s2 2s2 2p1 1s2 2s2 2p2 1s2 2s2 2p3 1s2 2s2 2p4 1s2 2s2 2p5 1s2 2s2 2p6 Electron Configurations of Some Atoms(Stop P1 + 5)

17. Shorthand Notation for Orbitals • Combinations of first two quantum numbers; number of orbital types equals the shell number (n). • 1s • 2s, 2p • 3s, 3p, 3d • 4s, 4p, 4d, 4f • 5s, 5p, 5d, 5f, (5g) • 6s, 6p, 6d, 6f, (6g, 6h)

18. Refer to electron configuration worksheet

19. Agenda • Brain Teaser • Grade Worksheet • Review • Writing Electron Configuration • Notes: Orbital Diagram • Homework • Short Hand Electron Configuration • Orbital Diagram

20. Grade Homework • Refer to Worksheet (Arrangement of Electrons I)

21. Check for understanding (P6) • What is the principal quantum number for Ar? • What are the subshells? • How many sets of electrons are found in each subshell?

22. Aufbau Principle • Aufbau Principle: start with the nucleus and empty orbitals, then “build” up the electron configuration using orbitals of increasing energy

23. Electron Configurations • Electron Spin and Pauli Exclusion Principle: • Only two electrons can occupy a single orbital and they must have opposite spins

24. Electron Configurations • Hund's Rule: • When filling a subshell, such as the set of 3 p orbitals, place 1 electron in each before pairing up electrons in a single orbital

25. Electron Configurations • Arrangement of electrons in the orbitals is called the electron configuration of the atom • The ground state configuration can be predicted, using the Aufbau Principle, the Pauli Exclusion Principle, and Hund’s Rule. Electron configurations Filling _ rules.exe

26. How do we know what the filling order is? • What chemistry tool might we rely on?

27. Electron Configurations and the Periodic Table • Valence electron configurations repeat down a group

28. Ground state electron configurations • Example: Li • atomic number = 3 • nucleus has 3 protons • neutral atom has 3 electrons • 2 electrons in 1s orbital, 1 electron in 2s orbital 2s 1s

29. Different ways to show electron configuration Box notation Energy level diagram   2s 2s 1s 1s Spectroscopic notation Li 1s2 2s1 Read this “one s two”not “one s squared” Write the superscript 1.Don’t leave it blank

30. Practice • Review (on separate sheet of paper) • Electron Configuration • Orbital Diagram • Electron configuration worksheet

31. The last subshell in the electron configuration is one of these (row #) s (row # – 1) d (row #) p (row # – 2) f Using the Periodic Table

32. The f-block is inserted into to the d-block

33. Electron configuration of O • Atomic number of O = 8 so neutral atom has 8 e–

34. Electron configuration of Co • Atomic number of Co = 27 so neutral atom has 27 e–

35. Simplifying electron configurations • Build on the atom’s noble gas core • He 1s2 O 1s22s22p4 O [He]2s22p4 • Ar 1s22s22p63s23p6 Co 1s22s22p63s23p64s23d7 Co [Ar]4s23d7      1s 2s 2p                1s 2s 2p 3s 3p 4s 3d

36. Noble Gases • Far right of the periodic table • These elements are extremely unreactive or inert • They rarely form compounds with other elements

37. Noble Gas electron configurations • What is the electron configurations for Neon • Abbreviated way to write configurations • Start with full outer shell then add on • Br • Ba

38. Noble Gases • Neon- emits brilliant light when stimulated by electricity – neon signs- 4th most abundant element in the universe. • Helium- light non reactive gas- used balloons- inexpensive, plentiful and harmless • Radon- radioactive gas- can cause cancer- colorless, odorless emitted from for certain rocks underground

40. Why are we doing all of this? • Properties of atoms correlate with the number and energy of electrons • Electron configurations are used to summarize the distribution of electrons among the various orbitals

41. Practice 3-3 Practice Write the complete electron configurations and noble gas shorthand #1-4

42. Practice • Refer to a periodic table and write the electron configurations of these atoms. • Write the configurations using shorthand notation. • Zn • I • Cs

43. The f-block is inserted into to the d-block

44. Find the electron configuration of Au • Locate Au on the periodic table

45. Find the electron configuration of Au • Au [Xe] • The noble gas core is Xe

46. Find the electron configuration of Au • Au [Xe]6s2 • The noble gas core is Xe • From Xe, go 2 spaces across the s-block in the 6th row  6s2

47. Find the electron configuration of Au • Au [Xe]6s24f14 • The noble gas core is Xe • From Xe, go 2 spaces across the s-block in the 6th row  6s2 • Then detour to go 14 spaces across the f-block  4f14 • note: for the f-block, n = row – 2 = 6 – 2 = 4

48. Find the electron configuration of Au • Au [Xe]6s24f145d9 • The noble gas core is Xe • From Xe, go 2 spaces across the s-block in the 6th row  6s2 • Then detour to go 14 spaces across the f-block  4f14 • note: for the f-block, n = row – 2 = 6 – 2 = 4 • Finally go 9 spaces into the d-block on the 6th row  5d9 • note: for the d-block, n = row – 1 = 6 – 1 = 5

49. Electron configuration of ions • What is an ion? • How many electrons does Cl1- have? • What is the electron configuration for the chloride ion? • How many electrons does Ca2+ have? • What is the electron configuration for the calcium ion? • What do you notice?

50. Practice • Draw the orbital diagram for sulfur. • What ion does sulfur want to form and why? • Draw the orbital diagram for Potassium. • What ion does sulfur want to form and why?