Chapter 22-1 Bonding Basics

What is a Compound? Compound: 2 or more elements chemically combined

What is a chemical formula? A chemical formula states the elements that make up a compound AND how many atoms each element contains. Chemical formulas can contain subscripts which tell how many atoms there are for each element.

Count the Atoms H2O Hydrogen = Oxygen = NaCl Sodium = Chlorine = C6H12O6 Carbon= Hydrogen = Oxygen =

What if the formulas have a coefficient? 2 H2O Hydrogen = Oxygen = 3 NaCl Sodium = Chlorine = 2 C6H12O6 Carbon= Hydrogen = Oxygen =

What if formulas contain parentheses? Mg(OH2) K4Fe(CN)6 3 (NH4)2SO4

Write the name of the element and the number of atoms: CaF2 Be(OH)2 NO2 Al2(SO4)3 Na2CO3 2 S2F2

When are elements stable? Elements are stable when the outermost energy level contains the maximum number of electrons. For Hydrogen and Helium, that number is 2. For most other elements, that number is 8.

Stability To become stable, an element will form a compound. Valence electrons are either shared, lost or gained. Any element that loses or gains valence electrons is called an ion. Ions have a positive or negative charge.

Ion’s Charges Why would an ion have a charge if elements are neutral? An element that gives away V.E. would have more protons (+) than electrons (-). This element would then have a positive charge. An element that takes on electrons (more negative parts than positive) would have a negative charge. Overall, the entire compound is neutral.

Electron Dot Diagrams (Lewis Structures) Draw the electron dot diagrams for the following: Li Be C O F Ne

Chapter 22-2 Types of Bonds

Chemical Bonds A chemical bond is an attraction that forms to hold elements in a compound. Remember, elements will either share, lose or gain valence electrons to become stable. There are two types of bonds: ionic and covalent.

Ionic Bonds An ionic bond forms when valence electrons are either lost or gained. Ionic bonds form when a metal combines with a non-metal.

Ionic Bonds One example of an ionic bond is NaCl.

Ionic Bonds

Ionic Bonds Another way of showing these bonds is to use the Lewis structure or dot diagrams.

Characteristics of Ionic Bonds The compounds formed in an ionic bond are solids at room temperature, conduct, have a crystalline structure and a high melting point.

Covalent Bonds The second type of chemical bond is called covalent. Covalent bonds form when electrons are shared between elements. Covalent bonds form when non-metals combine together.

Covalent Bonds

Characteristics of Covalent Bonds Covalent bonds form compounds that can be a liquid or gas at room temperature that are poor conductors, have a low boiling/melting point and are flammable. There are a few solids formed by covalent bonds. These tend to be soft, squishy compounds.

Practice Drawing the Compound and Decide if it is Ionic or Covalent Mg and I

Practice Drawing the Compound and Decide if it is Ionic or Covalent C and H

Practice Drawing the Compound and Decide if it is Ionic or Covalent Na and O

Practice Drawing the Compound and Decide if it is Ionic or Covalent

Practice Drawing the Compound and Decide if it is Ionic or Covalent C and O

Practice Drawing the Compound and Decide if it is Ionic or Covalent Al and Cl

Practice Drawing the Compound and Decide if it is Ionic or Covalent Na and O

Practice Drawing the Compound and Decide if it is Ionic or Covalent

22-3 Naming Ionic Compounds and Writing Formulas

Naming Binary Compounds A binary compound is a compound that contains only two elements. To name a binary compound, the element with a positive oxidation number is listed first. List the full name. This will always be a metal! Then write the root of the negative ion (always a non-metal)………..and add the letters IDE.

What is an oxidation number? An oxidation number is the charge an ion has due to forming an ionic bond.

Name these ionic compounds! KCl CrO3 CaO Al2O3 BaBr2 KI CaSe

Binary Formulas Now we will work backwards. Read the name of the compound, and figure out the formula. First, write the symbol of the element with a positive oxidation number. Second, write the symbol of the element with a negative oxidation number.

Make the compound neutral by making the number of positive charges equal the number of negative charges. Ex: Li is 1+ and N is 3- so you would need three Li to balance the N. Final compound name is Li3N.

Figure out the Formulas! Magnesium Fluoride Copper Oxide Aluminum Chloride Calcium Hydride Beryllium Sulfide Cesium Bromide Barium Nitride