Valence Electrons and Electron Configuration Explaining the arrangement of electrons 08/26 to 08/28

White Board Practice Use your lab materials to answer: 1.Ionization energy _______ from left to right across a period. 2.Put the elements in order of increasing ionization energy: N, F, B, Li Increases Li, B, N, F

White Board Practice Use your lab materials to answer: 1.Ionization energy _______ from top to bottom down a group. 2.Put the elements in order of increasing ionization energy: Sr, Ca, Ba, Ra, Be decreases Ra, Ba, Sr, Ca, Be

White Board Practice Use your lab materials to answer: 1.Electronegativity_______ from left to right across a period. 2.Put the elements in order of increasing Electronegativity: Cl, P, S, Mg, Na Challenge: Cl, P, S, Ba, Cs Increases Na, Mg, P, S, Cl Cs, Ba, P, S, Cl

White Board Practice Use your lab materials to answer: 1.Electronegativity_______ from top to bottom down a group. 2.Put the elements in order of increasing electronegativity: Na, Rb, K, Li, Fr Challenge: Na, K, Li, O, C decreases Fr, Rb, K, Na, Li K, Na, Li, C, O

White Board Practice Use your lab materials to answer: 1.Atomic Radius_______ from left to right across a period. 2.Put the elements in order of increasing atomic radius: Ca, Ti, Br, K Challenge: Li, Be, Na, K, O decreases Br, Ti, Ca, K O, Be, Li, Na, K

White Board Practice Use your lab materials to answer: 1.Atomic Radius_______ from top to bottom down a group. 2.Put the elements in order of increasing atomic radius: Na, Rb, K, Li, Fr Challenge: Na, K, Ra, B, F Increases Li, Na, K, Rb, Fr F, B, Na, K, Ra

Unit 2 Intro Unit 2 is Chemical Bonds… Before we begin putting compounds together we have to learn a few more rules about atoms that will help us predict what chemical bonds will form.

Think Pair Share Describe the pictured substances.

White Board Practice: Review 1.Why are the noble gases the least reactive elements? 2.What are groups? 3.What are periods?

White Board Practice: Answers 1.Why are the noble gases the least reactive elements? They have a full shell of valence electrons. 2.Groups are columns 3.Periods are rows

Write: groups tell us # valence electrons

Write: periods tell us energy levels

Unit 2 Day 1 Notes: Electrons Take out a sheet of paper. Title it: Unit 2 Day 1 Notes: Electrons

Think, Pair, Share Answer the question at the top of your notes: What does the number of protons tell us about an atom? Answer: The number of protons determines the atom’s identity. Example: All carbon atoms have 6 protons.

Notes: Electrons Electrons determine the chemical properties of an element. Only electrons react.

Notes: Electrons Valence electrons are electrons in the outside energy level of an atom. Valence electrons participate in chemical reactions. This atom has 1 valence electron. This is sodium. This atom has 1 valence electron. This is sodium.

1 question quiz! Write the answer on your white board: What on the periodic table tells us how many valence electrons an atom has?

Write: groups tell us # valence electrons Group 1 has 1 ve, group 2 has 2 ve, group 13 has 3, group 14 has 4, etc.

Notes: Electrons Lewis dot diagrams are a way to show the number of valence electrons. This atom has 1 valence electron. This is sodium. This atom has 1 valence electron. This is sodium. Na

Notes: Ions! Octet Rule: To form ions, atoms give or take enough electrons to have a full outer energy level. –They want the # of e- as the closest noble gas. This is usually 8. (Exception: Helium with 2.)

Ions Example O 6 ve Gain 2e- O 2-

Practice: Draw Lewis Dot Structures and ions for elements Fold you paper into an 8x4 grid. See the example. 2.Turn your paper so the long side is up. 3.Number the squares in the top left corner as shown here: 1In each square draw: (a) Lewis dot diagram, (b) # valence electrons, (c) ion formed

Practice: Draw Lewis Dot Structures and ions 3 Li 1 v.e. Lose 1 e- Li + In each square draw: (a) Lewis dot diagram, (b) number valence electrons, (c) ion formed using octet rule

Practice: Draw Lewis Dot Structures and ions Lewis Dot symbols show us how many valence electrons are in an atom. Use octet rule for ions. If you took away e- the ion is +, if you added e-, the ion is -. Li Li + In each square draw: (a) Lewis dot diagram, (b) # valence electrons, (c) ion formed

Think, Pair, Share A positive ion is called a cation. A negative ion is called an anion. Talk to your partner about which atoms form cations and which form anions.

Bonus Material Electron Configuration material is advanced material.

Electron Configuration A way to keep track of all those electrons! Write this down: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6

© 1998 by Harcourt Brace & Company S orbital P orbital D orbital F orbital Within the Energy Levels, electrons are arranged in 1 or more orbitals. Label the orbitals on your periodic table.

Orbitals S pdf Each orbital within a level has: different energies different shapes Different orientation in space

s-block1st Period 1s 1 # e - in sublevel Periodic Table & Electron Configuration Example - Hydrogen

p-block2nd Period 1s 2 2 e - in p sublevel Example - Carbon 2s 2 2p 2 X XX X XX Periodic Table & Electron Configuration

p-block2nd Period [He] Short Hand Configuration Example - Carbon 2s 2 2p 2 X XX X XX

S 16e - Valence Electrons (Outer shell) Core Electrons (Inner orbitals) 1s 2 2s 2 2p 6 3s 2 3p 4 Notation Longhand Configuration

Let’s Try It! 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 Practice! Write the electron configuration for the following elements: N, O, F, Ne, Na, Mg Write your answers under your Bohr models and Lewis Dot Structures for these elements.