Valence Electrons: ELECTRONS AVAILABLE FOR BONDING (the red ones) Chapters 15/6 Ionic Bonding

Valence Electrons Valence electrons The number of valence electrons largely determines the ______________________ of that element. For Groups 1A-7A, the number 1-7 is the number of valence electrons for that atom. Group 0 is an exception – you can think of it as group 8A because all the noble gases (except He) ________________________.

Valence Electrons Valence electrons are usually the only e- used to bond to other atoms. –

Generic Dot Notation An atom’s valence electrons can be represented by electron dot (AKA Lewis dot) notations. 1 valence e - X 2 valence e - X 3 valence e - X 4 valence e - X 5 valence e - X 6 valence e - X 7 valence e - X 8 valence e - X

Dot Notations – Period 2 Lewis dot notations for the valence electrons of the elements of Period 2. lithium Liberyllium Beboron Bcarbon C nitrogen Noxygen Ofluorine Fneon Ne

Octet Rule The Octet Rule was created by Gilbert Lewis in That’s why these diagrams are sometimes called ____________________________. An ___________________. Each noble gas (except He) has 8 valence electrons in their highest principle energy level, and the general configuration is ns 2 np 6 (_____________________________)

Metallic vs. Nonmetallic Elements Atoms of the metallic elements (including column 1A and 2A) tend to lose their outer shell valence e- so they can have a complete octet____________________________. Atoms of nonmetallic elements tend to ____ __________________________________ __________________________________ element to achieve their complete octet.

Cations and Anions If an atom loses a valence e- = ____________ If an atom gains a valence e- = ____________ Example: Sodium loses 1 e- Neutral: (Sodium) Na Ionic: (Sodium) Na + – Like Ne 1s 2 2s 2 2p 6 The change is written as follows: – Na· Na + + e -

Cations Cations of group 1A alkali metals ______ Cations of group 2A alkali metals ______ ·Mg· Mg e - For transition metals, the charges on the cations may vary. Note the Roman Numeral. Example: Fe has two:

Anions Anions are atoms or groups with a negative charge (extra electrons). Atoms of nonmetallic elements have relatively full valence shells and are looking to steal e- to make their shells full. Cl _______________neutral atom Cl - _______________anion Ar _______________now Cl - has Ar config.

Section 15.2 Ionic Bonding Ionic vs. Covalent Bonds Bonds: Forces that hold groups of atoms together and make them function as a unit.  Ionic bonds –  Covalent bonds –

Ionic Bonding Na: 1s 2 2s 2 2p 6 3s 1 now Na + Cl: 1s 2 2s 2 2p 6 3s 2 3p 5 now Cl -

Aluminum has three valence e- to steal, and the Bromine atoms would each like to steal one e-. So the Aluminum atom gives up three electrons and the Bromine atoms each receive one.

Sodium Chloride crystal lattice Ionic compounds form solid ______________at ordinary temperatures. Ionic compounds organize in a characteristic ___________________ alternating positive and negative ions. ____________________________________.

Properties of Ionic Compounds

Ch. 6 – Ionic Naming The Laws of Definite and Multiple Proportions The law of Definite Proportions states that in samples of any chemical compound, _____ ___________________________________ ___________________________________. The law of Multiple Proportions states that whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are _______________________________________.

Ions of Representative Elements Add – ide to anion name

Specific list of polyatomic ions you are accountable to memorize for the test -1 Ions-2 Ions-3 Ions NameFormulaNameFormulaNameFormula AcetateC 2 H 3 O 2 -1 SulfiteSO 3 -2 PhosphatePO 4 -3 HydroxideOH -1 SulfateSO 4 -2 NitrateNO 3 -1 CarbonateCO 3 -2 NitriteNO 2 -1 CyanideCN -1 Bicarbonate (hydrogen carbonate) HCO Ions AmmoniumNH 4 + Also know diatomic molecules: I 2 Br 2 Cl 2 F 2 O 2 N 2 H 2 and also H 2 O, NH 3 (ammonia), and CH 4 (methane)