1. Chapter 7: Completing the Model of the Atom

2. Class Activity (there is no BW) 1.Send 1 student from your team to pick up enough white boards and markers for each person. 1 paper towel per team 2.Draw a Bohr model for the element I assign to you.

3. Class Activity (there is no BW) 2. Now, find all other students with the same number of occupied energy levels. Starting with Hydrogen’s group, stand together. Next, lithium’s group, finally sodium’s group. What do you notice?

4. Class Activity (there is no BW) 3. Now, find all other students with the same number of valence. Starting with Hydrogen’s group, stand together. Then, Beryllium’s group, etc. Then, boron’s group, etc. What do students notice?

5. What the Periodic Table Tells Us 1. Columns are called “Groups” or “Families” – Main Group Elements are the tall ones! Groups 1 & 2, 13-18 They “follow the rules” pretty well. Behavior is predictable. They tell us how many ______ the atoms of these elements have. Groups #1&2 – Group # tells you how many Groups 13-18- subtract 10 from the Group # – Transition Elements are in between Main Group Elements Groups 3-12 Behavior is less predictable! – Inner Transition Elements are at the bottom of the P. Table

6. What the Periodic Table Tells Us 2. Rows are called “Periods” – They tell us the location of the _______ in atoms of these elements.

7. Use the P. Table to Make an e- Diagram for an Element Ex: Lithium Identify its Group #: 1 Identify its Period #: 2 Q: So how many valence e-s does a lithium atom have? And where are they located? A: 1 valence e- in the 2 nd energy level

8. Light: Electromagnetic Spectrum Energy can travel in waves. There are high energy and low energy waves. The ones we can see are called “the visible spectrum.” ROY G BIV Red is the low energy end: violet is the high energy end.

9. Movement of e-’s e-s can jump to higher energy levels if they absorb energy. They can’t keep the energy so they lose it and “fall back” to lower levels. When they do this, they release the energy they absorbed in the form of light.

10. Movement of e-s, cont. When e-s absorb energy, they do so in certain amounts. (They “jump” specific distances.) When they release energy, they do so in certain amounts. (They “fall” specific distances.) And they release light that has that amount of energy. Question: if e-s fall a long distance, they release a lot of energy. What is the color that is likely to be released? (red end or purple end of spectrum?)

11. Emission Spectrum Def: Each element has a characteristic set of colors that are given off when its e-s “fall back.” You can identify an element by its emission spectrum! Emission spectrum of hydrogen

12. Emission Spectrum (cont.) See Fig 7.4 on p 235 H has 4 spectral lines (4 colored lines) Mercury (Hg) has 11 lines! Ne has 20+ lines! Problem: there are more lines than you would expect if there are only a few energy levels. Hypothesis: There must be many sublevels in an energy level

13. Electron Sublevels Each electron has an “address,” where it can be considered to be located in the atom. Main energy level= “hotel” Sublevel = “floor” Orbital = “room” – Regions of space outside the nucleus – All orbitals in a sublevel have the same energy – 2 electrons max can fit in an orbital

14. Sublevels in Atoms See Fig 7.5 on p 235 Main energy level Types of sublevels # of orbitals# of electrons 1s1 2spsp 1 3 (4 total) 3spdspd 1 3 5 (9 total) 4-7spdfspdf 1 3 5 7 (16 total)

15. Orbitals s orbitals are spherical – There is only 1 orbital p orbitals are dumbbell shaped – There are 3 orbitals, all with = energy – Each is oriented on either x, y, or z axis – They overlap d orbitals have varying shapes – There are 5 orbitals, all with = energy f orbitals have varying shapes – There are 7 orbitals, all with = energy

16. Electron Configurations Electrons are always arranged in the most stable (lowest energy) way This is called“electron configuration”

17. Section 2: The Periodic Table & Atomic Structure Shape of p. table is based on the order in which sublevels are filled REGIONS OF THE P. TABLE (see p 244 of book) s REGION (“block”) - Groups 1 & 2 p REGION (block) - Groups 13-18 d REGION (block)- Groups 3-12 (Transition Elements) f REGION (block)- (Inner Transition Elements)

18. List sublevels from lowest to highest energy level (Using P.Table) 1. Always start with Period 1-go from L to R. 2. Go to Period 2-from L to R 3. Go to Period 3- from L to R 4. Continue 4-7 periods, L to R until you have completed the P. Table. Exception: elements in d block are 1 main E.L lower than the period where they are located Exception: elements in f block are 2 main E.L.s lower than the period in which they are located

19. Correct Order of Sublevels (lowest to highest energy) 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

20. Why Exceptions w/d & f block elements? When you get to the higher main E.L.’s, the sublevels begin to overlap.

21. E- configurations Use the P. Table to write the sublevels in increasing order, as previously instructed. Add a superscript next to each sublevel that shows how many e-s are in the sublevel Ex: Oxygen: 1s 2 2s 2 2p 4

22. Valence e-s Valence e-s are the electrons in the highest occupied main energy level. Identify the valence e-s by finding the “biggest big number” in your e- configuration. Ex: Oxygen: 1s 2 2s 2 2p 4 Question: WHAT IS THE BIGGEST BIG NUMBER YOU SEE? WHAT ARE THE VALENCE ELECTRONS?

23. Noble Gas Notation Short-cut way of showing e- configuration A Noble Gas is a Group 18 element. 1.Identify the noble gas in the period above your element of interest. Write this symbol in brackets. 2.Write the e- configuration for any additional e-s that your element of interest has, but the noble gas doesn’t have. Ex: Nitrogen: 1s 2 2s 2 2p 5 becomes [He] 2s 2 2p 5

24. Practice Noble Gas Notation Tungsten (W) E- configuration Noble Gas configuration

25. Arrow Orbital Diagram- Used to show e- configuration. SYMBOLS: A box represents an orbital – Label each box with the sublevel: 1s 2s 2p 2p 2p An arrow represents an electron – 2 arrows (e-s) in the same orbital face opposite directions. – Example: oxygen, see above ↑ ↓ ↑↑

26. Arrow Orbital Diagram- Used to show e- configuration. INSTRUCTIONS: Fill electrons from lowest to highest sublevel. Never place 2 e-s in the same orbital of a sublevel until you have placed one in each of the orbitals

27. Arrow Orbital Diagram: Practice

28. Regions or “Blocks” of the P. Table