6 more school days until Winter Break! December 2, 2016 Announcements & Reminders 6 more school days until Winter Break! Quiz re-takes this Friday and next Thursday( after the break) (Unit 3 Quiz 1) TASK: Be ready to show me completed reading questions for a stamp  DO NOW: What does the wave/particle paradox describe?

Take out a different-colored pen to make corrections

Reading- Quantum Mechanical Model Answers How is the quantum mechanical model unlike the Bohr Model? Unlike the Bohr Model, the quantum mechanical model does not state or involve the exact path of the electron around the nucleus Complete this sentence: “ 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” Explain how the quantum mechanical model is similar to the motion of a rotating propeller blade The quantum mechanical model is similar to the motion of a rotating propeller blade appears as a fuzzy cloud of where the propeller blade is while it’s rotating, just like a fuzzy cloud of electrons around the nucleus. What is an atomic orbital often thought of as? An atomic orbital is though of as the region of space in which there is a high probability of finding an electron

Reading- Quantum Mechanical Model Answers Copy the diagrams for the s, px, py, and pz orbitals from figure 5.5

Reading- Quantum Mechanical Model Answers Write one phrase summarizing each of the three electron filling rules (Aufbau, Pauli, Hund) Aufbau- Electrons occupy lowest energy levels (n) first before moving up to higher levels Pauli Exclusion Principle- An atomic orbital may hold up to two electrons, each with a different spin Hund’s Rule- Electrons do not “double-up” until all the orbitals contain at least 1 electron Looking at Table 5.3, how many unpaired electrons does Nitrogen have? Which rule is this an example of? Nitrogen has 3 unpaired electrons. This is an example of Hund’s Rule. Electrons cannot pair up, until all of the orbitals have at least 1. 10. Answer Section Assessment question 12 on page 136. (Use figure 5.7 to arrange the following sublevels in order of decreasing energy: 2p, 4s, 3s, 3d, and 3p) 3d4s3p3s2s

We can know 4 pieces of information about the location of any electron within an atom. 1. Energy Level (n) Distance from the nucleus Options: 1 – 7 2. Sublevel (l) Shape 3. Magnetic Orientation (lm) Direction the shape is pointing (think; x, y, z) 4. Spin (ls) How the electron is spinning (the options are up or down) We write an up electron as a half arrow up (↑) and a down electron as a half arrow down (↓)

1) Energy Level (n)

2) Shape (l) Spherical, Dumbbell, Other

Shape of S- Orbitals

Shape of P-Orbitals

Shape of D- Orbitals

Shapes Also, g sublevels are a theoretical thing…but we haven’t made any elements that require them yet.

Shapes d sublevels look like… (don’t worry about the orientation, you need to know there are 5 of them): f sublevels look like…? (you need to know there are 7 of them)

Number of electrons in each sublevel Number of Orbitals Maximum # of electrons (two per orbital) s p d f 1 2 3 6 5 10 7 14

3) Magnetic (lm) Rotation around 3-dimensional space

4) Spin (ls) Direction of electron’s spin

This table summarizes what we can know. Type of information Label What it represents How many options? How many e- can it hold? Energy Level n Distance from the nucleus n=1 through n=7 2n2 Sublevel l Shape n = 1  1 sublevel (s) n = 2  2 sublevels (s, p) n = 3  3 sublevels (s, p, d) n = 4  4 sublevels (s, p, d, f) Level 1 = ______ Level 2 = ______ Level 3 = ______ Level 4 = ______ Level 5 = ______ Magnetic lm Orientation of Orbital (which direction it is pointing) Depends on the number of sublevels. p-orbitals follow the x, y, and z axes (one orbital per axis) (each orbital can hold 2 electrons) Spin ls How electron is spinning Up = + ½ Down = - ½ The spinning of electrons generates an electric field. For 2 electrons to occupy the same orbital they must have opposite spin. 2 8 18 32 50

Quantum Mechanics Model Dance Electrons are in energy levels (there are 7) Orbitals have different shapes (sphere and dumbell, and others) Orbitals have different orientations (x,y,z) Two electrons in orbitals have opposite spins

Welcome to Hotel Smurfminion! HOTEL RULES From the Bottom Up: Rooms must be filled from the ground floor up. Fill the one room on the first floor before starting to put new tenants on the second floor. Then fill the s room before the p rooms. At higher floors the order might change a bit. Singles First: the owner of the building wants to have the tenants spread out as much as possible. For that reason singles are placed in rooms before couples. If couples must be placed into a room then all of the other rooms on that floor must already have a single in them. Opposites Only: When two individuals are placed in a room, one must be a minion and the other must be a smurf. No two minions or two smurfs in the same room!

The same rules apply for electrons! ELECTRON RULES From the Bottom Up: Energy levels must be filled from the lowest energy level to the highest Singles First: Single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals. Opposites Only: A maximum of two electrons may occupy a single orbital, but only if the electrons have opposite spins.

There are names for these rules… Aufbau Principle Hund’s Rule Pauli Exclusion Principle

Aufbau Principle Each electron occupies the lowest energy orbital i.e. Electrons are Lazy! All orbitals related to an energy level are of equal energy. i.e. The three 2p orbitals are the same energy level.

Hund’s Rule Analogy: Seats on a bus Single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals. i.e. Electrons are unfriendly! Analogy: Seats on a bus

Hund’s Rule Example

Pauli Exclusion Principle A maximum of two electrons may occupy a single orbital, but only if the electrons have opposite spins. spin-- Electrons have an associated “spin,” either one way or the other, like a top. These spins are called “spin up” and “spin down.” Exceptions to filling order are copper, chromium and some others- because half-filled shells are more stable, so an atom may borrow an electron from next s shell to half fill a lower energy level.

Correct or Incorrect?

This diagram helps show the differences in energy for each sublevel within an electron cloud. Working from bottom to the top, you can see how each atom’s electrons fill. Use it to write in the electrons for a neutral atom of Phosphorous (15 electrons)

Neutral atom of Phosphorous (15 electrons)

Complete the following diagram for Magnesium. How many electrons will a neutral atom of magnesium have? ____ If you were to summarize the information about Magnesium, how might you write it more simply?

Quantum Theory Review: According to the quantum theory, are electrons particles, waves, or both? What are the 4 quantum numbers, and what do they describe?

HOMEWORK: Complete “Practice- Orbital Notations & Electron Configurations” DUE TOMORROW!!!