Pauli Exclusion Hunds Rule Orbital Diagrams Valence Electrons

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

• 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

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 1 s 2 s 2 px 2 py 2 pz 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 • 1 s 2 2 p 4 • Oxygen has six valence electrons (2 s 2 and 2 p 4)

Valence Electrons (skip) • Write the electron configuration for potassium • 1 s 2 2 p 6 3 s 2 3 p 6 4 s 1 • Potassium has 1 valence electron (4 s 1)

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 1 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 10 4 p 5 Bromine has seven valence electron (4 s 2 and 4 p 5)

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