General Physical Science
Semester #2
Unit 2: Bonding and Molecules
Exam Date: March 10, 11 2015
Oregon State Content Standards
H.1P.1 Explain how atomic structure is related to the properties of elements and their position in the Periodic Table.
Explain how the composition of the nucleus is related to isotopes and radioactivity.
H.1P.2 Describe how different types and strengths of bonds affect the physical and chemical properties of compounds.
Objectives:
Meeting benchmark
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I will be able to use the periodic table to predict the oxidation number of the elements.
I will be able to identify how elements form chemical bonds and the role of electrons in bonding.
I will be able to use oxidation numbers to predict what ions might bond successfully.
I will be able to use oxidation numbers to predict chemical formulas of compounds.
I will be able to write the correct chemical name of compounds when given the chemical formula.
I will be able to use the periodic table and atomic mass units of the elements to calculate the formula mass of
compounds.
Exceeding benchmark
1. I will be able to explain why an ion has a particular charge by describing what happens to the electrons and
balance of charges during ionization.
2. To show my ability to exceed the benchmarks I will use words, drawing, mathematical relationships or other
methods to further analyze patterns and/or relationships in the benchmarks.
Vocabulary
Ion: an atom which has lost or gained an electron. It has a charge known as the oxidation number.
Oxidation Number: the charge an atom has after it gains or loses an electron (becomes an ion).
Molecule: the smallest possible portion of a compound. For example, "Two atoms combined to form one molecule of
the compound NaCl."
Compound: a substance made of two or more elements
Ionic bond: a chemical bond formed between ions of opposite charge.
Formula Mass: a way to compare the masses of molecules of different compounds. Determined by adding up the atomic
mass units of all the atoms in compound.
Atomic Mass Unit: a measurement used to compare the relative mass of atoms. (1/12 of a Carbon-12 atom)
Chemical Formula: a representation of a compound that includes the symbols and numbers of atoms in the compound.
Monoatomic ion: ions that contain only one type of atom.
Polyatomic ion: ions that contain more than one type of atom.
Homework for this unit:
1. Read 327-332. Problem #1 on page 348.
2. Read 334-336. Concept Review #1-4 on page 347.
3. Problems #3,4,5 on page 348.
Name:
_____
Unit 2
Review Questions
1. What is an ion?
2. Why do atoms bond with other atoms?
3. Why are the noble gases (elements on the far right column of the periodic table) nonreactive/unstable?
4. List two elements which Sodium would be likely to bond with.
5. List two elements which Sodium would not be likely to bond with.
6. Is Oxygen likely to gain or lose electrons to end up with a complete outer shell?
7. What is Oxygen’s oxidation number?
8. How many valence electrons does Oxygen have?
9. List an element/ion that Oxygen would NOT be likely to bond with. Explain why.
10. List an element/ion that Oxygen would be likely to bond with. Explain why.
11. What is the chemical formula for a compound of Calcium (+2) and Chlorine (-1)?
12. Calculate the formula mass for H2O. (H = 1.01 amu, O = 16.00 amu)
Answers.
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An atom which has lost or gained an electron.
To fill their outer shells and become neutral.
They are nonreactive because their outer shells (valence shells) are full.
Fluorine, Chlorine.
Lithium, Beryllium.
Oxygen is likely to gain electrons.
-2
6
Sulfur. Sulfur is lacking two electrons in outershell and so it has an oxidation # of -2 and does not give up electrons.
Magnesium. Magnesium has 2 valence electrons (oxidation# of +2 which it is likely to give up in order to have a full outer shell.
CaCl2
18.02 amu