4.1 - Intro to Chemical Bonding 2. Molecular Formula 3. Empirical Formula 4. Ionic Bond 1. Chemical Bond 5.Metallic Bonds 7.Polar Covalent vs. Non-Polar Covalent 6.Covalent Bonds

Do Now CO is carbon monoxide. CO 2 is Carbon Dioxide. Compare and contrast these two compounds. Write everything you know or can assume about the compounds.

Do Now You and a friend order one large pizza. -How many slices and people do you have? -How many slices per person do you have? You and three friends order one large pizza. -How many slices and people do you have? -How many slices per person do you have? You and seven friends order three large pizzas. -How many slices and people do you have? -How many slices per person do you have?

1.Chemical Bond The attractive force that holds atoms or ions together

2.Molecular Formula Indicates the NUMBER of atoms in a molecule O H H # of H = 2 # of O = 1 Molecular Formula = H 2 O

C H H C H H Ethene Molecule 2 Carbon 4 Hydrogen Molecular Formula = C 2 H 4

3.Empirical Formula Indicates the RATIO of atoms in a molecule (divide by GCF) C H H C H H 2 Carbon 4 Hydrogen Empirical Formula = CH 2 GCF = 2

3 Carbon 6 Hydrogen Empirical Formula = CH 2 GCF = 3 C H H C H H C H H

4. Ionic BondAn attraction between oppositely charged ions (between metals and nonmetals) Na 1+ Cl 1- Opposites Attract!!! Table pop out

How do you know it’s ionic? - Usually a metal and non metal - Electronegativity difference greater than Electronegativity Difference Ionic Bond

Ionic Bonds – Metal and Nonmetal Na Cl Li F Sodium Chloride Lithium Fluoride Mg O Magnesium Oxide

2. Oxidation Number The charged ion the atom is likely to form (vertical columns) Varies usually +2 to +7 Oxidation Number

5. Metallic Bonds Fe +2 An attraction of positively charged ions and the electrons around them (between metals) e-e- e-e- e-e- e-e-

6.Covalent Bonds When atoms share one or more pairs of electrons (between non-metals) P 9 N 10 P 9 N 10

How do you know it is covalent? - Usually between nonmetals - Difference in electronegativity less than Electronegativity Difference Covalent Bond

7.Polyatomic Ion A covalently bonded molecule that carries an ionic charge. Sulfate = SO 4 2- Sulfite = SO 3 2- Nitrate = NO 3 1- Nitride = NO 2 1-

4.1 - Intro to Chemical Bonding 2. Molecular Formula Indicates the number of atoms in a molecule 3. Empirical Formula 4. Ionic Bond 1. Chemical Bond 5.Metallic Bonds 7.Define Polyatomic Ion 6.Covalent Bonds Indicates the ratio of atoms in a molecule The attractive force that holds atoms or ions together An attraction between oppositely charged ions (between metals and nonmetals) An attraction of positively charged ions and the electrons around them (between metals) When atoms share one or more pairs of electrons (between non-metals) A covalently bonded molecule that carries and ionic charge

This apparent charge, called the oxidation number, represents the charge that an atom would have if electrons were transferred completely to the atom with the greater attraction for them in a given situation Predicting Bond Types The difference in electronegativities of two elements can be used to predict the nature of the chemical bond. Bond type can be described as belonging to one of three classes: nonpolar covalent polar covalent ionic When differences are 1.7 or greater, the bond is usually ionic. Less than 1.7, the bond is usually covalent, and unless the difference is less than 0.5 the bond has some degree of polarity. Differences of less than 0.5 are considered to be nonpolar.