1. Science Starter Na, Ag, Br, Se, Ne, He, Cs, Hg
Of the elements above, which elements are:
Metals
Metalloids
Nonmetals
Good conductors of heat and electricity
Semiconductors
Liquids at room temperature

2. Objective
SWBAT describe the properties and why they occur of the major groups of the Periodic Table
SWBAT identify the “blocks” of the periodic table, as per the quantum mechanical model

3. AGENDA Science Starter Classifying the Elements
Bohr Model/Valence Electrons
Intro to Quantum Mechanic Model
Exit Ticket

4. Announcements
Unit 2 Quiz Monday 2/15

5. Unit 2: The Electron Classifying the Elements
February 8, 2016

6. Unit 2: The Electron
February 9, 2016
Classifying the Elements

7. Classifying the Elements (just take notes for now, you will label these a little later…)
Group 1: Alkali Metals
Highly reactive, soft solids
Group 2: Alkaline Earth Metals
Groups 3-12: Transition Metals
Group 17: Halogens
Group 18: Noble Gases
Stable and unreactive
May have to be saved until Tuesday?

8. VIDEO: ALKALI METALS
Bananas are a great source of ________. Alkali metals… …and how they react…

9. ALKALINE EARTH METALS Ca + O2  CaO
What do you need to keep your bones healthy?
Ca + O2  CaO
Stupid things people do…

10. VIDEO: HALOGEN GROUP What chemical goes in pools?

11. VIDEO: NOBLE GASES What are colorful lit signs made out of?

12. CONSENSUS Elements in the same group have similar chemical properties
Elements on the far right (the Noble gases) are the least reactive
Elements on the far left (the alkali metals) are the most reactive.

13. Elements are sorted into groups or families (vertical columns) based on their chemical properties
… but what determines these chemical properties?

14.  1. Working Overtime
2. Do Without
3. Teddy Bear
4. Shot in the Dark
5. Eiffel Tower
6. Long Island

15. A VERY Brief History…
When do you think the very first idea of “the atom” was suggested?

16. DEMOCRITUS 460 – 370 B.C.
First model of an atom!

17. PLUM PUDDING MODEL

18. ERNEST RUTHERFORD 1871-1937 Nucleus Theory 1910
alpha particle gold foil experiment
An atom’s mass is mostly in the nucleus
The nucleus has a positive charge (Moseley)
Electrons in fixed orbit

19. RUTHERFORD MODEL (Jimmy Neutron Style…)

20. NIELS BOHR 1885-1962 Planetary Model 1913 “Thought” experiment
Nucleus surrounded by orbiting electrons at different energy levels
Electrons have definite orbits
“Thought” experiment

21. BOHR’S MODEL

22. So what is the… BOHR MODEL??
A scientist, Niels Bohr received the Nobel Prize for discovering that electrons are not just randomly surrounding the nucleus.
The Bohr Model says that electrons exist is very specific energy levels surrounding the nucleus.
Electrons ONLY exist at these levels, not in between. We call these levels “SHELLS”

23. Let’s take a look.

24. ELECTRONS
The chemical properties of ALL elements are determined by their VALENCE ELECTRONS.
Valence Electron: electrons on the outermost energy level.

25. How to Calculate Valence Electrons
What did we say was true about elements in the same group?
They behave the same chemically!!
This is all because of their VALENCE ELECTRONS!
Elements in the same group have the same number of valence electrons!
Pull out your periodic tables!

26. Group 1 (alkali metals) have 1 valence electron

27. Group 2 (alkaline earth metals) have 2 valence electrons

28. Group 13 elements have 3 valence electrons

29. Group 14 elements have 4 valence electrons

30. Group 15 elements have 5 valence electrons

31. Group 16 elements have 6 valence electrons

32. Group 17 (halogens) have 7 valence electrons

33. Group 18 (Noble gases) have 8 valence electrons, except helium, which has only 2

34. Transition metals (“d” block) have 1 or 2 valence electrons

35. Lanthanides and actinides
(“f” block) have 1 or 2 valence electrons

36. VALENCE ELECTRONS 1 8 2 3 4 5 6 7
1 or 2
1 or 2

37.  1. No one to Blame
2. Right between the eyes
3. Jack in the Box
4. Down Payment
5. Left Overs
6. Bedspread

38. Evidence for the Bohr model
Bohr showed that hydrogen energy levels existed as steps, not continuous.
Atomic motion has properties of waves.
Electrons can act as waves=light=energy.
We have the start of a model that relates energy and matter.
Only works for hydrogen
Fails for multi-electrons atoms because it doesn’t consider electron-electron interactions
Charged particles in motion gives off energy
Bohr model violates the law of conservation of energy
Problems with the Bohr Model

39. Ernst SCHRÖDINGER and Werner HEISENBURG
Quantum Mechanical Model 1926
Electrons are in probability zones called “orbitals”, not orbits and the location cannot be pinpointed
Electrons are particles and waves at the same time
Developed quantum numbers based on theories of Einstein and Planck

40. ORBITALS

41. Quantum Mechanical Model of the Atom
Experiments later showed that electrons could be treated as waves
just as light energy could be treated as particles
The quantum mechanical model treats electrons as waves and uses wave mathematics to calculate probability of finding the electron in a particular region in the atom
Schrödinger Wave Equation
can only be solved for simple systems, but approximated for others 13

42. Quantum Mechanical Model – the probability of finding an electron
Orbit is a circular path
Orbital is a probability map

43. Orbital Shapes: the probability an electron will be found

44. D orbitals