Pauli Exclusion, Hund’s Rule, Orbital Diagrams, Valence Electrons, Unpaired Electrons

Evaluation/ Assessment Objective Today I will be able to: Explain the behavior of electrons based on Pauli’s exclusion Principle and Hund’s Rule Illustrate the location of an electron by drawing an orbital diagram Determine the number of unpaired electrons in an atom Identify the location of valance electrons in an atom Evaluation/ Assessment Informal assessment – student responses when reviewing electron configuration problems, orbital diagrams and valence electrons. Listening to group interactions on practice sheets Formal Assessment – collecting and analyzing responses to electron configuration worksheet 2 and the where is the electron lab. Reviewing responses to the exit ticket

Lesson Sequence Warm – Up Explain: principles, rules and diagrams of electron configurations Elaborate: Students complete orbital diagrams worksheet Evaluate: Students will draw orbital diagrams on the board and explain their answers (informal assessment) Explain: Valance Electrons Notes Elaborate: Students complete a valance electrons worksheet Evaluate: Students will share responses to the worksheet Exit Ticket

Warm - Up Write the electron configuration for the following elements: Magnesium Iron Arsenic What is the abbreviated configuration for Sulfur?

Objectives Today I will be able to: Explain the behavior of electrons based on Pauli’s exclusion Principle and Hund’s Rule Illustrate the location of an electron by drawing an orbital diagram Determine the number of unpaired electrons in an atom Identify the location of valance electrons in an atom

Homework STEM Fair Conclusion Due Tuesday

Agenda Warm – Up Collect Flame Test Lab Notes Pauli Exclusion Principle, Hund’s Rule, Orbital Diagrams Orbital Diagram Practice Review Practice as a class Valence Electron Notes Valance Electron Practice Exit Ticket New Seats for B-day

Electron Configuration Rules and Principles

Aufbau Principle Electrons fill in lower energy levels before filling in higher energy levels

Pauli Exclusion Principle An orbital can hold a max of 2 e- To occupy the same orbital, they must spin in opposite directions If 2 e- occupy an orbital, they are said to be “paired” If only 1 e- is present in an orbital, it is “unpaired”

Pauli Exclusion Principle

Hund’s Rule e- occupy orbitals so that a max number of unpaired e- result More stable arrangement

Orbital Diagram Shows the electrons in their sublevels Represented with arrows

Orbital Diagram 1s 2s 2px 2py 2pz H ↑ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↑ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ He C ↑ ↓ ↑ ↓ ↑ ↑ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ Ne

Complete the Electron Configuration and Orbital Diagram Practice Worksheet

Review the Electron Configuration and Orbital Diagram Practice Worksheet

Valence Electron Notes

Valence Electrons Electrons in the outermost energy level Determines the number of electrons an atom gains, loses, or shares These are the electrons that are involved in bonding

Valence Electrons (skip) Write the electron configuration for oxygen 1s2 2s2 2p4 Oxygen has six valence electrons (2s2 and 2p4)

Valence Electrons (skip) Write the electron configuration for potassium 1s2 2s2 2p6 3s2 3p6 4s1 Potassium has 1 valence electron (4s1)

Valence Electrons Exceptions are the d and f sublevels! Use the number of electrons in the last s sublevel (and the p sublevel, if available) Write the electron configuration for Bromine 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5 Bromine has seven valence electron (4s2 and 4p5)

Foreshadowing: Octet Rule Most atoms want 8 electrons in their outermost level OR full s and/or p sublevels Atoms will form bonds to achieve the desired amount of electrons Atoms are most stable when they have a full outer shell

Complete Valence Electrons Worksheet

Review Valence Electrons Worksheet as a class

Exit Ticket For the element Chlorine: Write the electron configuration Write the abbreviated electron configuration Draw an orbital diagram Explain why you drew the electrons in the location of the orbital's that you did Determine the number of valence electrons

Exit Ticket Mol Monday # 1 How many molecules of CO are in 5.0 grams of CO?