Name:Chemistry Unit Review

Include the page number in the book where you found each answer!

  1. 3 Types of Sub-Atomic Particles, their Location in an Atom, and how to find their number from the periodic table (Section 1.1)

Particle / Location / How to find using table
Protons / Nucleus / Atomic number
Neutrons / Nucleus / Mass # - atomic #
Electrons / Outside of nucleus/ electron cloud / Same as atomic number/ protons
  1. Why are atoms considered to be neutral particles? (section 1.1)

The positive protons cancel out the negative electrons.

  1. What are valence electrons and why are they important? How can the periodic table be used to determine the valence electrons of an atom? (section 1.2)

Valence electrons are the outermost electrons. They are what forms the bond between atoms.

Rules: Groups 1, 2: same as group #Groups 13-18: Group # - 10

  1. Determine the number of valence electrons for the following atoms. (section 1.2):H-1Ca-2O-6Ne- 8
  1. What are the noble gases? Describe their ability to bond (section 1.2).

Noble gases are in group 18. They have a full outer shell and don’t form bonds.

  1. Explain how Mendeleev arranged the periodic table of elements and how it is arranged on the modern periodic table. (section 2.1)

Mendeleev organized the table by atomic mass (Mass number) and the modern table is organized by atomic number

  1. The Periodic Table has how many Groups of Elements? What are 2 things that groups have in common?

Groups: 18Same # of valence electrons and elements in each group have similar properties

  1. The Periodic Table has how many Periods? What do periods have in common? (section2.1)

Periods: 7Elements in the same period have the same number of electron energy levels

  1. Name the 3 classes of elements and list the properties of each. (section 2.2)
  2. Metals (malleable, conduct electricity and heat, ductile, shiny, solid at room temp)
  3. Nonmetals (opposite properties compared to metals- doesn’t conduct electricity, gases, etc.)
  4. Metalloids (some metal and some nonmetal properties…semiconductors)
  5. Explain the role of a subscript in a chemical formula. (section 3.1)

Subscripts tell you the number of atoms of each element in a chemical formula.

  1. What are the 3 types of bonds we discussed in this unit? Define each and give an example. (section 3.2, 3.3, and 3.4)

1. ionic (metal and nonmetal- NaCl, MgCl2)

2.covalent (all nonmetals- CO2, H2O)

3.metallic (all metals- iron, steel, aluminum)

  1. Compare Atoms and Ions. (section 3.2)

Atoms are neutral and ions have a charge atoms and ions are both forms of an element

Atoms have the same number of protons as electrons (ions do not)

  1. Explain how to name Ionic and Covalent bonds. (section 3.2 and 3.3)

Ionic: Metal first, then nonmetal…-ide on end of last element/ no prefixes

Covalent: left to right then bottom beats top…ide on end of last element/ USE prefixes

  1. Name the following Ionic Compounds (section 3.2):MgCl2magnesium chlorideNaClsodium chloride
  1. Name the following Covalent Compounds (section 3.3):CO2carbon dioxideN2Odinitrogen monoxide

COcarbon monoxideCCl4carbon tetrachloride

  1. Define Diatomic Molecule and give 3 Examples. (section 3.3)molecules made up of 2 atoms of the same element

Examples: O2, H2, Cl2

  1. What is a Chemical Reaction? (section 4.1)

A process in which some substances change into different substances (Reactants form Products)

  1. Describe the Four Signs of a Chemical Reaction. (section 4.1)
  • Color change
  • Temperature/ Energy change (heat, sound, light)
  • Formation of a gas (smoke, bubbles)
  • Formation of a solid (precipitate)
  1. In the proper sequence, describe what happens during a Chemical Reaction. (section 4.1)
  • Original bonds break
  • Atoms rearrange
  • New bonds form
  1. Define the terms Products and Reactants. Write a balanced chemical equation and label the products and reactants. (section 4.1)

Reactants = starting materials (before the arrow)Products = ending materials (after the arrow)

(reactants) 2Na + Cl2 2NaCl (products)

  1. Insert Coefficients and Balance the following Chemical Equations (section 4.2):
  2. __2____H2 + _____O2 __2___H2O

b. ___3__Mg + ______N2 ______Mg3N2

  1. What does the Law of Conservation of Mass state (section 4.2)?

Atoms (mass) cannot be created nor destroyed. Equations must be balanced or have the same number of atoms on each side of the equation because of this law.

  1. List and define the five Types of Chemical Reactions (section 4.3)

1. synthesis (two or more combine to form 1 product)

2. decomposition (1 reactant breaks down into multiple products)

3. single replacement (1 element replaces part of a compound)

4. double replacement (2 compounds switch partners)

5. combustion (fuel and oxygen yields water and carbon dioxide)

  1. What does it mean for a chemical reaction to be Exothermic (section 4.4)?

Gives off more energy than it absorbs (feels hot)

  1. What does it mean for a chemical reaction to be Endothermic (section 4.4)?

Absorbs more energy than it releases (feels cool)

  1. What does the Law of Conservation of Energy state (section 4.4)?

Energy cannot be created nor destroyed. It transfers from one form to another.

  1. Define Activation Energy and give 3 examples. (section 4.4)

Activation energy is the amount of energy needed for a reaction to get started. Examples include: sparks, friction using a match, light, etc.)

  1. List 5 Factors Affecting Rate of Reaction and explain how they affect reaction rate. (section 4.4)

1. temperature (higher temp increases rate because particles are moving faster)

2. surface area (smaller pieces increases rate because more of the reactants are exposed)

3. concentration (higher concentration increases rate because)

4. catalyst (chemical that speeds up a reaction)

5. inhibitor (chemical that slows down or stops a reaction)

29. Define the following components of an experiment:

  1. Independent variable: the part of an experiment that the scientist changes on purpose (what they are testing)
  2. Dependent variable: the part of an experiment that changes as a result (what the scientist is measuring)
  3. Control Variables: parts of the experiment that stay the same so you know it is the independent variable causing the change
  4. Control Group: What you are using to compare your data to (your baseline, normal, or standard) …often without the independent variable
  5. Sources of Error: What would cause your group to get different results compared to other groups