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Chapter 7 Expanding the Theory of the Atom. l Democritus and Leucippus - Matter is made up of indivisible particles l Dalton - one type of atom for each.

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Presentation on theme: "Chapter 7 Expanding the Theory of the Atom. l Democritus and Leucippus - Matter is made up of indivisible particles l Dalton - one type of atom for each."— Presentation transcript:

1 Chapter 7 Expanding the Theory of the Atom

2 l Democritus and Leucippus - Matter is made up of indivisible particles l Dalton - one type of atom for each element l Page 231

3 Thomsons Model l Discovered electrons l Plum-Pudding model

4 Rutherfords Model l Discovered the nucleus l Electrons moved around l Mostly empty space

5 Bohrs Model Electrons move in circular orbits at different levels. Amounts of energy separate one level from another.

6 Bohrs Model Nucleus Electron Orbit Energy Levels

7 Bohrs Model Increasing energy Nucleus First Second Third Fourth Fifth } l Further away from the nucleus means more energy. l There is no in between energy l Energy Levels

8 The Quantum Mechanical Model l Energy is quantized. l A quanta is the amount of energy needed to move from one energy level to another.

9 l Energy levels for electrons. l Orbits are not circular. l It can only tell us the probability of finding an electron a certain distance from the nucleus. The Quantum Mechanical Model

10 l Electron cloud l Area where there is a chance of finding an electron. The Quantum Mechanical Model

11 Atomic Orbitals l Principal Quantum Number (n) = the energy level of the electron. l These are called atomic orbitals l Regions where there is a high probability of finding an electron.

12 l Starts at first energy level l Spherical shaped l Each s orbital can hold only 2 electrons l Called the 1s, 2s, 3s, etc. orbitals. S orbitals

13 P orbitals l Start at the second energy level l 3 different directions l 3 different shapes l Each can hold 2 electrons

14 P Orbitals

15 D orbitals l Start at the third energy level l 5 different shapes l Each can hold 2 electrons

16 F orbitals l Start at the fourth energy level l Have seven different shapes l 2 electrons per shape

17 F orbitals

18 Summary s p d f # of shapes Max electrons Starts at energy level 121 362 5103 7144

19 Increasing energy 1s 2s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 3d 4d 5d 7p 6d 4f 5f

20 By Energy Level l First Energy Level l only s orbital l only 2 electrons l 1s 2 l Second Energy Level l s and p orbitals are available l 2 in s, 6 in p l 2s 2 2p 6 l 8 total electrons

21 By Energy Level l Third energy level l s, p, and d orbitals l 2 in s, 6 in p, and 10 in d l 3s 2 3p 6 3d 10 l 18 total electrons l Fourth energy level l s,p,d, and f orbitals l 2 in s, 6 in p, 10 in d, ahd 14 in f l 4s 2 4p 6 4d 10 4f 14 l 32 total electrons

22 Electron Configurations l The way electrons are arranged in atoms. l Aufbau principle - electrons enter the lowest energy first. l Overlap of orbitals of different energies.

23 Electron Configuration Phosphorus: - Need to account for 15 electrons

24 l The first two electrons go into the 1s orbital l only 13 more Increasing energy 1s 2s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 3d 4d 5d 7p 6d 4f 5f

25 l The next electrons go into the 2s orbital l only 11 more Increasing energy 1s 2s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 3d 4d 5d 7p 6d 4f 5f

26 The next electrons go into the 2p orbital Increasing energy 1s 2s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 3d 4d 5d 7p 6d 4f 5f

27 The next electrons go into the 3s orbital only 3 more Increasing energy 1s 2s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 3d 4d 5d 7p 6d 4f 5f

28 Increasing energy 1s 2s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 3d 4d 5d 7p 6d 4f 5f The last three electrons go into the 3p orbitals. They each go into separate shapes 3 unpaired electrons 1s 2 2s 2 2p 6 3s 2 3p 3

29 The easy way to remember 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f

30 Fill from the bottom up following the arrows 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 1s 2 2s 2 4 electrons

31 Fill from the bottom up following the arrows 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 1s 2 2s 2 2p 6 3s 2 12 electrons

32 Fill from the bottom up following the arrows 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 20 electrons

33 Fill from the bottom up following the arrows 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 38 electrons

34 Fill from the bottom up following the arrows 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 56 electrons

35 Fill from the bottom up following the arrows 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6 7s 2 88 electrons

36 Fill from the bottom up following the arrows 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6 7s 2 5f 14 6d 10 7p 6 108 electrons

37 Exceptions to Electron Configuration

38 Orbitals fill in order l Lowest energy to higher energy. l Half filled orbitals have a lower energy. l Makes them more stable. l Changes the filling order

39 Write these electron configurations l Titanium - 22 electrons l 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 2 l Vanadium - 23 electrons l 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 3 l Chromium - 24 electrons l 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 4 is expected l But this is wrong!!

40 Chromium is actually l 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 3d 5 l Why? l This gives us two half filled orbitals. l Slightly lower in energy. l The same principal applies to copper.

41 Coppers electron configuration l Copper has 29 electrons so we expect l 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 9 l But the actual configuration is l 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 3d 10 l This gives one filled orbital and one half filled orbital. l Remember these exceptions


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