20

=Chapter 20: Chemical Bonds=

Section One: Sability Bonding Vocabulary: chemical formula: tells what elements a compound contains and the exact number of the atoms of each element in the unit of a compound chemical bond: the force that holds atoms together in a compound

Picture Questions: 1. Table salt is a crystalline solid and is edible. 2. Group 2 can go with group 16.

Reading Check: 1. A chemical formula tells you how many electrons are in a compound

Section Review: 1. Compare and Contrast the properties of the individual elements that combine to make salt withthe compound salt. Sodium is a soft, silvery metal and chorline is a grreenish-yellow gas. These form sodium-chloride or salt which is a white crystalline solid.

2. Identify what that formula BaF2 tells you about this compound. This compound has one atom of Barium and two atoms of flourine.

3. Identify the forces that hold atoms and molecules together at the atomic level. Give an example of how these forces are invovled in a chemical reaction. The electric forces between oppositly charged protons and electrons so these forces cause comppounds to form.

4. Explain why some elements are stable on their own whils others are more stable in compounds. It all depends on the number of electrons in the elements outer level. If the outer level is full the element is stable.

5. Describe why chemical bonding occurs. Give two examples of how bonds can form. Chemical bonding occurs when an element needs electrons, or needs to lose or share electrons.

6. Think Critically The label on a box of cleanser states that it contains CH3COOH. What elemens are in this compound. How many atoms of each element can be found in a unit of CH3COOH?

Applying Math: 7. Use precentages Given that the molecular weight of Mg(OH)2, magnesium hydroxide, is 58.32, what precentage of this compound is oxygen?

Section Two: Types of Bonds Vocabulary: ion: charged particles becasue it now has either more or fewer electrons than protons ionic bond: the force of attraction between opposite charges of ions in an ionic compound covalent bond: that attraction that forms between atoms when they share electons molecule: a neutral particle that forms as a result of electron sharing polar molecule: one that is slightly positive ended and has a slightly negative end although the overall molecule is neutral nonpolar molecule: one in which electrons are shared equally in bonds

Picture Questions: Electrons make the size vary. Hydrogen

Reading Check: The suscript A polar molecule is a molecule that has a slightly positive and slightly negative end but is overall neutral.

Section Review: 1. Explain why an atom makes an ionic bond only with certain other atoms. The attraction of the forces must be between opposite charges.

2. Compare and contrast the possession of electrons in ionic and covalent bonds. In ionic bonds electrons gain or lose. In covalent bonds electrons are shared.

3. Name the types of particles formed by covalent bonds. A neutral particle forms as a result of electron sharing. It is called a molecule.

4. Think critically. From the following list of symbols, choose two elements that are likely to form an ionic bond: O, Ne, S, Ca, K. Next, select two elements that would likely form a covalent bond. Explain.

5. Concept map. Using the following terms, make a network-tree concept map of chemical bonding: ionic, covalent, ions, positive ions, negative ions, molecules, polar, and nonpolar. Types of Bonding Ionic Covalent ion molecules which can be polar positive or negative nonpolar

6. Applying math. Solve one-step equations. Aluminum oxide, Al2O3, can be produced during space shuttle launches. Show that the sum of the positive and negative charges in a unit of Al2O3 equals zero.

Section Three: Writing Formulas and Naming Compounds Vocabulary: binary compound: one that is composed of two elements oxidation number: tells you how many electrons an atom has gained, lost of shared to become stable polyatomic ion: a positively or negatively charged, covalently bonded group of atoms hydrate: a compound that has water chemically attached to its ions and weitten into its chemical formula

Picture Questions: CaSO4 X 2H20

Reading Questions: 7 hepta

Section Review:

1. Use formulas. Write formulas for the following compounds: potassium iodide, magnesium hydroxide, aluminum sulfate, and chlorine heptoxide. KI,MgH2,2AS3

2. Use formulas. Write the names of the compounds: KCl, Cr2O3, Ba(ClO3)2, NH4Cl, and PCl3. Potassium Choride Barium Oxide Ammonium Chloride Phospnorus Chloride

3. Name Mg3(PO4)2 x 4H20, and write the formula for calcium nitrate trihydrate. Madnesium Phospate Tetrahydrate

4. Think critically. Explain why sodium and potassium will or will not react to form a bond with each other. They both have the same charge so they would never be equal unless combined with a third, negativiealy charged element.

5. Applying math. Solving one-step equations. The overall charge on the polyatomic sulfate ion, found in some acids, is 2-. Its formula is SO4 2-. If the oxygen ion has a 2- oxidation number, determine the oxidation number of sulfur in this polyatonic ion. Positive Four 4+