End Catalyst The periodic table is arranged by what? What is the number the arrow is point to referred to as? What does it tell us? End

Homework Review and Exit Slip Grading

Lecture 1.4 – Electron Configurations and the Octet Rule

Build an Atom Simulator Build an atom pHet simulator (http://phet.colorado.edu/en/simulation/build-an-atom). Link is uploaded to the website. Students should work with a partner on the guided inquiry handout.

Today’s Learning Target LT 1.4 – I can determine the number of valence electrons for an element, draw a Bohr electron configuration for an element and explain how the Octet rule leads to the formation of ions.

Essential Point Atoms do not have a charge Neutral atoms have equal numbers of protons and electrons. So, atomic number also tells us the number of electrons.

Periodic Table Nomenclature Groups – Vertical columns on the Periodic Table Periods – Horizontal rows on the Periodic Table Periods Push Across Groups Go Down

Bohr Model of the Atom Ask a student to remind you what the Bohr model of the atom stipulated. How was this different from Rutherford’s and Thomson’s model of the atom?

Electron Orbits The first orbit holds 2 electrons Every other orbit after the first orbit holds 8 electrons.

Valence Electrons Valence Electrons – The number of electrons that are in the outermost electron orbit

Class Example Draw the Bohr electron configuration for lithium. Determine the number of valence electrons.

Table Talk Draw the Bohr electron configuration for sodium. Determine the number of valence electrons.

Stop and Jot Draw the Bohr electron configuration for potassium. Determine the number of valence electrons.

SHORTCUT! All elements in the same group (1A, 2A, etc.) have the same number of valence electrons.

Summarize

Around the World There are 8 problems posted around the room. You and your partner must complete all 8 as a team. When completed, show to Mr. Astor You must complete all 8 problems.

5 Minute Break

The Octet Rule Atoms like to have a full outer valence shell They will gain or lose electrons in order to have an outer orbit with 8 electrons (or 2 if it is the first energy level). They will gain/lose based on what is easiest.

Class Example Draw the Bohr electron configuration for beryllium after it has satisfied the Octet Rule.

Table Talk Draw the Bohr electron configuration for magnesium after it has satisfied the Octet Rule.

Stop and Jot Draw the Bohr electron configuration for calcium after it has satisfied the Octet Rule.

SHORTCUT! All elements in the same group, gain/lose the same number of valence electrons.

Ions When atoms gain/lose electrons, they gain a charge. Ion – An atom or molecule where the number of protons does not equal the number of electrons, giving the atom a charge. Cation – A positively charged ion Anion – A negatively charged ion

Cats make people feel positive Way to remember the difference between a cation and an anion.

Class Example Determine the ion that forms for fluorine after the Octet Rule has been satisfied.

Table Talk Determine the ion that forms for nitrogen after the Octet Rule has been satisfied.

Stop and Jot Determine the ion that forms for oxygen after the Octet Rule has been satisfied.

SHORTCUT! All elements in the same group, form ions with the same charge.

Summarize

Rally Coach 1) Each of you will pair up with the person that is across from you. 2) Pick who is Partner A and who is Partner B. 3) You will grab a whiteboard and a marker. 4) When I say go. Partner A will read the question aloud to Partner B. Then, Partner A will walk Partner B through the steps that need to be taken to get the final answer. MAKE SURE TO DO ALL THE STEPS! 5) I will call time after 30 seconds and each pair will raise their board in the air. 6) After I ask groups about your answers, the partners switch roles and Partner B does the questioning and reasoning and Partner A does the writing.

Question 1 Draw the Bohr electron configuration for Neon.

Question 2 Draw the Bohr electron configuration for Sulfur

Question 3 Determine the number of electrons Phosphorus would gain or lose to satisfy the octet rule.

Question 4 Determine the number of electrons magnesium would gain or lose to satisfy the octet rule.

Exit Ticket Draw the Bohr structure for Phosphorus How many electrons must it gain/lose to satisfy the Octet Rule? What will the charge of its ion be? What is wrong with the drawing below?

Rate Yourself Based on the exit ticket and your current level of understanding, rate yourself 1 – 4 on LT 1.1 - 1.4

Closing Time Homework 1.3 – Octet Rule and Bohr Structures Quiz Wed on LTs 1.1 – 1.4