9 Oxidation NumbersThe oxidation number is equal to the charge of an atom after it has gained or lost electron(s)For example, we saw sodium (Na) lose an electron. The oxidation number would be +1.Chlorine gained an electron. What would be its oxidation number?
10 Characteristics of Ionic Compounds Made from a positive and a negative ion (such as Na⁺ and Cl⁻)The overall charge is neutral!Conduct electricity when melted or dissolved in waterIons in the liquid state can move more freelyHigh melting and boiling pointsUsually solid at room temperatureStrongest bonds!
11 Practice Magnesium + Oxygen Lithium + Fluorine Calcium + Oxygen Magnesium + ChlorineDraw Lewis dot structureOxidation numbersShow electron transfer
12 Ex Poster • • Element Name and Symbol I Can Bond With… (List and draw Lewis dot structures for bonds with 4 different elements)I am reactive because….My oxidation number is…..Bohr Model•Ex•Lewis Dot Model
13 Ionic Bonding Practice Magnesium and ChlorineLithium and Oxygen
14 Before You Leave… What is one thing you learned today? What is one question you still have?What is one thing you already know (or can predict) about covalent bonding?
15 Covalent Bonds Formed by atoms sharing electrons Usually formed between nonmetalsWeaker than ionic bonds
16 Characteristics of Covalent Bonds Low melting and boiling pointsDo not conduct electricityCan be solid, liquid, or gasCan share more than one pair of electronsDouble or triple bond
17 Covalent Practice Hydrogen and Hydrogen Chlorine and Chlorine Chlorine and HydrogenHydrogen and OxygenNitrogen and HydrogenCarbon and HydrogenOxygen and Oxygen
18 Independent PracticeH and BrP and ClS and OSi and ClC and O
19 Metallic Bonds Bonds between metal atoms Attraction between nucleus of one atom and the electrons of nearby atomsEnergy levels overlap so electrons move freely between atoms
20 Polyatomic Ions Contain both ionic and covalent bonds Have a positive or negative charge overallExample: baking soda (NaHCO3) is made from a bond between Na and a polyatomic ion (HCO3-)
21 Macromolecules Organic compounds Contain carbon Building blocks of lifeCarbohydrates (sugars)Lipids (fats/oils)ProteinsNucleic acids
22 Quiz ReviewIdentify the following bonds as either ionic or covalent, draw the Lewis dot structures, and write the oxidation number (if applicable).Mg and OCl and ClH and NK and OLi and F