PLEASE Choose the BEST answer.

1. The zigzag line on the periodic table divides

a. alkali metals and transition metals

c. semimetals and transition metals

b. metals and nonmetals

d. inert gases and halogens

2. The smallest particle into which an element can be divided and still be the same substance is a (n)
a. electron

b. proton

c. atom

d. molecule

3. Electrons are particles that

a. help make up the nucleus and have no charge

b. help make up the nucleus and are positively charged

c. are located outside of the nucleus and are negatively charged

d. are located outside of the nucleus and have no charge

4. If you found a Carbon 13 atom, you would know that

a. it has 13 protons

c. it has 13 neutrons

b. it has 13 electrons

d. it has 7 neutrons

5. What particles make up the nucleus?

a. electrons and neutrons

b. electrons and protons

c. protons and neutrons
d. electrons, protons, and neutrons

6. Neutrons are particles that

a. help make up the nucleus and have no charge

b. help make up the nucleus and are positively charged

c. are located outside of the nucleus and are negatively charged

d. are located outside of the nucleus and have no charge

7. The current model of the atom suggests that

a. proton clouds surround the nucleus
b. electron clouds surround the nucleus
c. electrons travel in definite paths around the nucleus

d. the exact path of a moving electron can be predicted

8. The mass number minus the atomic number is equal to the number of

a. protons and neutrons

b. protons

c. protons and electrons

d. neutrons

9. Mendeleev arranged the elements

a. density

b. melting point

c. how they look (appearance)

d. atomic mass

10. Which of the following is NOT found on the periodic table?

a. the atomic number of each element

b. the symbol of each element

c. the density of each element

d. the atomic mass of each element

Experiment: effect of solution concentration on reaction rate you have learned that as the concentration of reactants increases, there will most likely be a greater number of collisions, and hence increase the rate of a reaction. in this experiment, you will see a demonstration of this, with a twist. there will be three reactions going on in this experiment. objectives determine how solution concentration can affect the rate of a reaction. the first reaction will be a reaction of the iodide ion (i-1) with hydrogen peroxide (h2o2) in an acidic solution. this reaction produces a slightly orange solution. in our experiment, we will add some orange food coloring to make this solution more orange. 2 h+ (aq) + 2 i- (aq) + h2o2 (aq) ⟶ i2 (aq) + 2 h2o (l) the next reaction will be between the iodine and starch i2 + starch ⟶ i2-starch complex (blue-black) so, when starch is added to the iodine solution made from the first reaction, the solution will turn black immediately, so it is difficult to find the rate of reaction. in order to be able to time this reaction, you will slow it down with another reaction. adding ascorbic acid will react with the iodine, reducing the concentration of the iodine available to react with the starch. c6h8o6 (aq) + i2 (aq) ⟶ 2i- (aq) + c6h6o6 (aq) + 2 h+ (aq) when the ascorbic acid is used up, the remaining iodine molecules can react with the starch and form the black color. the more ascorbic acid you add, the slower the reaction to form the iodine-starch complex will be. use your data and observations to complete the assignment. analysis and conclusions submit your data and the answers to these questions in the essay box below. what was your hypothesis? plot your data as drops of ascorbic acid vs. time. as the concentration of ascorbic acid was increased, did the rate of the formation of the iodine-starch complex increase or decrease? explain your answer in terms of the chemical reactions involved. was your hypothesis correct? make a general rule about the effects of concentration of reactants on reaction rates. for practice, the molecular formula for ascorbic acid is c6h8o6, and you used 6 g in this experiment, calculate the molarity of the ascorbic acid. now calculate the concentration in moles per drop (assume 1 ml = 20 drops).