Chapter 5 – Models of the Atom

Do Now – Current Events and Chemistry Objective – Chap 4 Review 5.1 Models of the Atom Homework – Pg. 132 # 1-6

Supersonic Man How does this relate to anything we have talked about already this year? Write you idea in your notes

Tevatron

CERN Super Collider

Review Questions – Pg 125 # 1-9

1. C 2. A 3. B 4. B E 7. False, True 8. True, False 9. True, True – Correct explanation

Review what we know Democritus Dalton Thompson Rutherford

The Bohr Model

Carbon Magnesium

Silicon Fluorine

Do Now –Draw Bohr Models of K, O, and Ar Any old work to turn in? Objective – 5.1 and 5.2 The Quantum Mechanical Model Homework – Pg 136 # 10-13

The Electron Cloud Model

Where is the propeller?

The Quantum Mechanical Model The Quantum Mechanical Model determines the allowed energies an electron can have and how likely it is to find the electron in various locations around the nucleus.

Atomic Orbitals Atomic Orbitals are thought of a regions of space around a nucleus where a given electron is likely (90%) to be.

Do Now – Check neighbor’s homework and give an effort grade of √-, √, √+ Objective – Electron Configuration in Atoms HW - Pg 136 # 10-13

Pg 132 # It couldn’t explain why metals give of characteristic colors when heated or explain the chemical properties of elements. 2. An electron is found only in a specific path or orbital around the nucleus 3. It determines allowed energies and where it is likely to be located. 4. The have different shapes. 5. By gaining or losing a quantum of energy. 6. In an atom, electrons have certain fixed energy levels. To move to a different level requires the emission or absorption of an exact amount of energy or quantum. The energy of the electron is said to be quantized.

Calculations Average Mass Total Mass (g) / Number in Sample = Average Mass (g) A-Regular g / 17 =.8882g B-Peanut=2.6078g C-Pretzel=2.4417g Total=1.7861g Relative Abundance Number in Sample / Total Number of Particles = Relative Abundance A-Regular 17 / 38 = B-Peanut= C-Pretzel= Total= 1.0 Percent Abundance Relative Abundance x 100 = Percent Abundance A-Regular x 100 = % B-Peanut =23.68 % C-Pretzel= % Total= 100 %

Review of 5.1 Principal Number of Energy Levels Sublevels Orbitals 1 11 s (1 orbital) 2 22 s (1 orbital), 2 p (3 orbitals) 3 33 s (1 orbital,) 3 p (3 orbitals), 3 d (5 orbitals) 4 44 s (1 orbital,) 4 p (3 orbitals), 4 d (5 orbitals), 4 f (7 orbitals) Chlorine has 17 electrons 1s 2 2s 2 2p 6 3s 2 3p 5

Electron Configuration How atoms are arranged to get the most stable atom possible. Three Rules 1. Aufau Principle 2. Pauli Exclusion Principle 3. Hund’s Rule

Aufbau Principle Electrons will occupy the orbitals of the lower energy levels first.

Pauli Exclusion Principle An orbital may describe 2 electrons, in other words, orbitals can hold 2 electrons If two electrons occupy the same orbital they must have opposite spins ↑↓

Hund’s Rule Electrons will occupy orbitals of the same energy level in such a way that make the spin direction as large as possible. In other words, every orbital at the same energy level gets one electron before any get a second

Exceptions to the Configuration Rules What do you think would happen if an atom were to differ from the configuration rules?

There are small differences between the 3d and 4s energy levels and even smaller differences between the 5f and 6d levels

Friday, October 8 th Do Now – Review Homework Worksheet Get out your copy of the periodic table Obj – Physics and the Quantum Mechanical Model HW – Pg. 146 # 16 – 19 Lab Handout Part 1

Zinc 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 Magnesium 1s 2 2s 2 2p 6 3s 2

3p 3 There are 3 electrons in the p sublevel of the 3 rd energy level.

Neon8A – Nobel Gas2 nd period Argon8A – Nobel Gas3 rd period Vandium5B – 4 th period

Do Now – Get out the pre lab you wrote Objective – 5.3 Physics and the Quantum Mechanical Model HW – Pg. 146 # 16-20

Light Amplitude Wavelength (λ) Frequency (v) Hertz (Hz)

C = λ v The speed of light is the product of the wavelength and the frequency. Light is electromagnetic radiation

Atomic Spectra When atoms absorb energy, the electrons move to a higher energy level. These electrons lose energy by emitting light when they return to a lower energy level. The frequencies emitted are unique for different elements and combinations of elements

The light emitted by an electron moving from a higher energy level to a lower (not always ground) has a frequency directly proportional to the energy change of the electron.

Spectrum

Atomic Spectrum

Quantum Mechanics

Heisenberg Uncertainty Principle It is impossible to know exactly both the velocity and position of a particle (electron) at the same time.

Flame Test Lab Do Now – Pre-labs out with pen/pencil and calculator. All bags away and table clear. Obj – Flame Test Lab HW – Pg. 153 # 1-18

Calculations ∆E = h c λ (note that this is in m and not nm)

Calculations ∆E = h c λ (note that this is in m and not nm) You need to convert from nm to m. Calcium was orange with frequency of 600nm 600 nm · 1 m = 1 x 10 9 nm can you do this ?

Understand Scientific Notation 600 x 1/ 1 x 10 9 Means move decimal 9 places to the right. Think about how little of a meter you will have if you only have 600 nm move 9 places m or 6.0 x 10 -7

Understand Scientific How to Use Your Notation Calculator 600 x 1/ 1 x 10 9 Means move decimal 9 places EE to the right. Think about how EE 9 little of a meter you will have if you only have 600 nm. 0r move 9 places m or 6.0 x = 6 E -7 or 6.0x nd ˄