1. Which of the following is true about photosynthesis?
A) It is an exothermic reaction.
B) It is an endothermic reaction.**
C) It produces carbon dioxide.
D) It occurs in animals.
2. Atomic theory is
A) subject to change if new information is discovered. **
B) a solution to the problem of diering isotopes. C) unchangeable.
D) a descriptive table that lists all of the elements.
3. Two nonmetals from Group 16 are likely to form a-
A) triple and ionic bond.
B) double and ionic bond.
C) triple and covalent bond.
D) double and covalent bond.**
Use your reference copy of the Periodic Table to answer questions 4 and 5.
4. How can you describe the location of magnesium (Mg, atomic number 12) on the periodic table?
A) nonmetal
B) metalloid
C) Group 2, Period 3**
D) Group 3, Period 2
5. How many valence electrons does magnesium (Mg) have?
A) 12
B) six
C) three
D) two**
6. Which reaction is exothermic?
A) cellular respiration**
B) photosynthesis
C) baking soda + vinegar
D) melting ice
7. You are creating a carbon cycle poster. What could you include in the poster to demonstrate the cycling of carbon?
A) a rock falling
B) shells fossilizing
C) an eagle breathing**
D) the sun shining
8. Which chemical equation is balanced?
A) H20 H2 + 2O2
B) 2H20 2H2 + O2**
C) 2H2O H2 + 2O2
D) H20 2H2 + 2O2
11. When two hydrogen atoms bond with one oxygen atom to form water, what happens to the electrons?
A) Each hydrogen atom donates its electron to the oxygen atom
B) The oxygen atom donates an electron to each hydrogen atom
C) A pair of electrons is shared at each of the hydrogen-oxygen bonds**
D) No electrons shared or donated
12. Why is frying an egg an example of a chemical change?
A) atoms are lost during the reaction as bonds are broken
B) atoms are gained during the reaction as new bonds form
C) the products have dierent properties than the reactants**
D) the properties of the reactants are seen in the products
13. How did the discovery of the electron change the atomic model?
A) It disproved the earlier idea of an indivisible atom. **
B) It confirmed that atoms are very tiny.
C) It exposed fraudulent experiments conducted by unqualified scientists.
D) It proved that atoms are easier to see than once believed.
14. A student analyzed two diagrams of a nitrogen atom. Both diagrams showed seven protons in the nucleus, but the number of neutrons diered.
What are the two nitrogen atoms?
A) electrons
B) isotopes**
C) covalent bonds
D) ionic bonds
15. What is an arrangement of all elements showing the repeating pattern of their properties?
A) atomic model
B) electron dot diagram
C) periodic table**
D) chemical formula
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