1 The History of the Development of the Human Understanding of the Atom. After Rutherford...

Niels Bohr Hydrogen atoms were known to emit specific wavelengths of light after being excited. Focusing on the particle properties of electrons, Bohr constructed a quantum model to explain this emission phenomenon. He proposed that electrons orbited the nucleus at specific radii, also called energy levels.

3 Problems with the Bohr Model Electrons required specific (quantized) amounts of energy to move from one energy level to another, and emitted characteristic amounts of energy when returning the ground-state energy levels. Bohr’s model predicted that electrons were more tightly bound when they were closer to the nucleus, and that atoms emitted energy when electrons dropped energy levels, energy would be released. With a lot of assumptions and adjustments, the Bohr Model fit the one-electron hydrogen atom pretty well, but failed for all other atoms. It was soon recognized that it was fundamentally wrong, and a new approach was needed.

4 Wave Properties of Electrons In the mid-1920s, Erwin Schrodinger, building on the dual nature of matter, began focusing on the wave-like properties of the electron. By visualizing electrons as standing waves (like guitar strings) instead of "orbiting" particles, the distinct energy levels observed by experiments could be explained.

5 Wave Properties of Electrons If electrons are waves, then the wavelength of the electron must 'fit' into any orbit that it makes around the nucleus in an atom. All orbits that do not 'fit' are not possible, because wave interference will rapidly destroy the wave amplitude and the electron (wave) wouldn't exist. This 'interference' effect leads to discrete (quantized) energy levels and the discrete 'line' spectrum of the hydrogen atom: The standing wave diagram above is a visualization of why (if electrons have wave-like properties like wavelength) only certain orbitals are allowed. It is not meant to say that electrons move in wavy orbits around the nucleus.

6 The Wave Equation Schrödinger developed a mathematical model based on wave mathematics to describe the position of electrons in an atom. For a given atom, Schrödinger's Equation has many solutions, and these different solutions are called orbitals. These orbitals do not describe actual orbits like Bohr's model, but, instead, describe areas of probability of where an electron might be found. This is just one of many different forms the equation can take.

Understanding the Arrangement of Electrons Inside Atoms The Results of Schrödinger’s Equation and Quantum Mechanics Electron configuration Orbital Notation

8 The Wave Equation After 1913 when Bohr mathematically described the energy states of the single- electron hydrogen atom, but his theory could not be used for multi-electron atoms, Schrödinger developed the wave equation. This equation solves to describe the energy states and areas of probability of where electrons are located within multi-electron atoms. This is just one of many different forms the equation can take.

9 Suppose you needed to communicate the seating in the auditorium by without the use of the picture with just letters and/or numbers. You might symbolize the seats in the following manner: Sections Rows Seat numbers etc

10 First Row - Electron Configuration H: 1s 1 s orbitals are sphere-shaped and there is one on each and every energy level. He: 1s 2 first energy level 1 electron “s” orbital

11 Second Row - Electron Configuration Li: 1s 2 2s 1 Be: 1s 2 2s 2 B: 1s 2 2s 2 2p 1 There are three “p” orbitals on any given energy level, level 2 and above. They are lobe-shaped, oriented in the x, y, z planes. 1A2A8A 3A4A5A6A7A Li Be B 1B2B3B4B5B6B7B8B9B10B

12 Second Row, continued.... Li: 1s 2 2s 1 Be: 1s 2 2s 2 B: 1s 2 2s 2 2p 1 C: 1s 2 2s 2 2p 2 N: 1s 2 2s 2 2p 3 O: 1s 2 2s 2 2p 4 F: 1s 2 2s 2 2p 5 Ne: 1s 2 2s 2 2p 6 1A2A8A 3A4A5A6A7A LiBeBCNOFNe 1B2B3B4B5B6B7B8B9B10B

13 Third Row - Electron Configuration Na: 1s 2 2s 2 2p 6 3s 1 Mg: 1s 2 2s 2 2p 6 3s 2 Al: 1s 2 2s 2 2p 6 3s 2 3p 1 Si: 1s 2 2s 2 2p 6 3s 2 3p 2 P: 1s 2 2s 2 2p 6 3s 2 3p 3 S: 1s 2 2s 2 2p 6 3s 2 3p 4 Cl: 1s 2 2s 2 2p 6 3s 2 3p 5 Ar: 1s 2 2s 2 2p 6 3s 2 3p 6 1A2A8A 3A4A5A6A7A NaMg 1B2B3B4B5B6B7B8B9B10B AlSiPSClAr ↑↓ ↑ and Orbital Notation ↑↓ ↑ ↑ ↑↓ ↑ ↑ ↑ ↑↓ ↑↓ ↑ ↑ ↑↓ ↑↓ ↑↓ ↑ ↑↓ ↑↓ ↑ ↑↓

14 1s, 2s, 3s orbitals highest probability low probability highest probability low probability

15 The Periodic Table is Shaped to Help You s - two columns, 2 electrons maximum, 1 orbital p - six columns, 6 electrons maximum, 3 orbitals 1A2A8A 3A4A5A6A7A 1B2B3B4B5B6B7B8B9B10B s orbitals p orbitals

16 Third Row Elements

17 Fourth Row K: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 Ca: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 Sc: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 1 There are five “d” orbitals on any (allowed) energy level. 21 protons is enough + attraction to pull the electrons closer to the nucleus to the 3rd energy level. Thus you need to remember that when you are in the 4th row of the table, you are filling the 3d orbitals. Why is it 3d not 4d?

18 How electrons “fill” an atom

19 How to create an electron configuration diagram Let’s continue……back to the 4 th row

20 Fourth Row K: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 Ca: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 Sc: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 1 Ti: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 2 V: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 3 Cr: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 4 Mn: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 5 Fe: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 Co: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 7 Ni: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 8 Cu: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 9 Zn: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10

21 finish the Fourth Row s (d) & p K: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 Ca: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 (Transition Metals - “d” group) Ga: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 1 Ge: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 2 As: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 3 Se: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 4 Br: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5 Kr: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6

22 The Periodic Table is Shaped to Help You s - two columns, 2 electrons maximum, 1 orbital p - six columns, 6 electrons maximum, 3 orbitals d - ten columns, 10 electrons maximum, 5 orbitals s orbitals d orbitals p orbitals 1A2A8A 3A4A5A6A7A 1B2B3B4B5B6B7B8B9B10B

23 What are the shape of “d” orbitals? Yikes ! You do not need to know these shapes.

24 Fifth Row s & d Rb: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 Sr: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 Y: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 1 Zr: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 2 Nb: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 3 Mo: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 4 Tc: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 5 Ru: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 6 Rh: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 7 Rd: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 8 Ag: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 9 Cd: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10

25 Fifth Row Representative Elements s (d) & p Rb: 1s 2 2s 1 3s 2 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 Sr: 1s 2 2s 2 3s 2 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 Transition Metals - “d” group In: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 1 Sn: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 2 Sb: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 3 Te: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 4 I: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 5 Xe: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6

26 The Periodic Table is Shaped to Help You s - two columns, 2 electrons maximum, 1 orbital p - six columns, 6 electrons maximum, 3 orbitals d - ten columns, 10 electrons maximum, 5 orbitals s orbitals d orbitals p orbitals 1A2A8A 3A4A5A6A7A 1B2B3B4B5B6B7B8B9B10B

27 Sixth Row Cs: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 1 Ba: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 so pause to note where we are in the periodic table clearly we need a new orbital type as we are headed into a new “block” on the table. This type is called “f” La: 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 1 Ce: 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 2 Pr: 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 3 Nd: 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 4 Pm: 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 5 Sm: 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 6 Etc, etc, etc through Yb: 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

28 Sixth Row continued..... Yb: 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 So where do we go from here? on to the “d” orbitals Lu: 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 1 Hf: 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 2 Ta: 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 3 Etc, etc, etc through Hg: 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 Tl: 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 1 Pb: 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 2 Bi: 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 3 Etc, etc, etc

29 Write the entire electron configuration 16 S 1s 2 2s 2 2p 6 3s 2 3p 4 28 Ni 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 8 60 Nd 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 4

30 Turn these entire e.c. into the condensed version of e.c. 16 S 1s 2 2s 2 2p 6 3s 2 3p 4 [Ne] 3s 2 3p 4 28 Ni 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 8 [Ar] 4s 2 3d 8 60 Nd 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 4 [Xe] 6s 2 4f 4

31 Name the element described by the condensed version of e.c. [Ne] 3s 2 3p 3 15 P [Ar] 4s 2 3d 10 4p 5 35 Br [Xe] 6s 2 4f 14 5d 3 73 Ta [Rn] 7s 2 5f 8 96 Cm

32 Name the element described by the single highest energy orbital. (Assume all lower orbitals are filled.) 2p 1 5B5B 4d 2 40 Zr 6p 5 85 At 5f 2 90 Th 4p 8 No such element

33 Write the single highest energy orbital to describe the element. (Assume all lower orbitals are filled.) 12 Mg »3s 2 43 Tc »4d 5 65 Tb »4f 9 82 Pb »6p 2

34 So what shape are “f” orbitals? 7 different orbitals, each of which is 4-lobed you do NOT need to know these shapes

35 Just what do thos s, f, d, p letters mean? s - sharp p - principal d - diffuse f - fundamental g, h, i... alphabetical

36 Write the orbital notation for these condensed electron configurations 16 S [Ne] 3s 2 3p 4 28 Ni [Ar] 4s 2 3d 8 60 Nd [Xe] 6s 2 4f 4 ↑↓ ↑↓ ↑ ↑ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑ ↑↓ ↑ ↑ ↑ ↑