1. The three particles that make up an atom are A.) protons, neutrons, and isotopes. B.) neutrons, isotopes, and electrons. C.) positives, negatives, and electrons. D.) protons, neutrons, and electrons.

2. The space surrounding the nucleus of an atom contains A.) protons. B.) electrons. C.) neutrons. D.) ions.

3. Which is the negatively charged particle located outside the nucleus of an atom? A.) electron B.) neutron C.) silicon D.) proton

4. If a neutral atom has 15 protons, then it will have _________ electrons. A.) 15 B.) extra C.) 14 D.) no

5. Which particle in the nucleus of an atom has a neutral charge? A.) carbon B.) neutron C.) electron D.) proton

6. The nucleus is made up of A.) protons and electrons. B.) electrons and neutrons. C.) protons and neutrons. D.) protons, neutrons, and electrons

7. Isotopes are atoms of the same element with the same number of protons and A.) a different number of electrons. B.) a different number of molecules. C.) a different number of neutrons. D.) the same number of neutrons.

8. One isotope of carbon differs from another in which way? A.) atomic number B.) number of neutrons C.) number of electrons D.) number of protons

9. If an atom contains 11 protons and 12 neutrons, its atomic number is A.) 1. B.) 11. C.) 12. D.) 23.

10. Which of the following terms describes a substance formed by the combination of two or more elements in definite proportions? A.) compound B.) isotope C.) nucleus D.) enzyme

11. A covalent bond is formed as the result of A.) transferring electrons. B.) sharing an electron pair. C.) transferring protons. D.) sharing a proton pair.

12. What type of ion forms when an atom loses electrons? A.) neutral B.) positive C.) negative D.) possibly positive or negative

13. What is the process that changes one set of chemicals into another set of chemicals? A.) cohesion B.) adhesion C.) chemical reaction D.) dissolving

14. _______ represents a formula for a chemical compound. A.) H B.) C C.) P D.) H2O

15. Which is the best description of activation energy? A.) Heat added to initiate a reaction. B.) Heat released as the reaction proceeds C.) Heat stored within the reactant D.) Heat stored within the product

16. Enzymes affect the reactions in living cells by changing the A.) products of the reaction. B.) speed of the reaction. C.) temperature of the reaction. D.) pH of the reaction.

17. How does an enzyme influence a biological reaction? A.) It increases the net energy difference B.) It decreases the activation energy C.) It increases the kinetic energy D.) It decreases the kinetic energy

18. Capillary action is the result of adhesion. Which aspect of water is responsible for this? A.) hydrogen bonds between water molecules B.) polar covalent bonds that join hydrogen and oxygen C.) nonpolar covalent bonds that enable partial charges D.) ionic bonds that enable electrons to transfer to hydrogen

19. The most abundant compound in most living things is A.) carbon dioxide. B.) water. C.) sodium chloride. D.) sugar.

20. When salt is dissolved in water, water is the A.) reactant. B.) solution. C.) solute. D.) solvent.

21. A substance with a pH of 6 is called A.) an acid. B.) a base. C.) both an acid and a base. D.) neither an acid nor a base

22. Solutions where H+ ions are produced A.) are catalysts B.) are acids. C.) are bases. D.) are enzymes.

23. A monosaccharide is a A.) carbohydrate. B.) lipid. C.) nucleic aci D.) protein

24. Which of the following organic compounds is the main source of energy for living things? A.) carbohydrates B.) lipids C.) nucleic acids D.) proteins

25. Which of the following is NOT a function of proteins? A.) store and transmit heredity B.) help to fight disease C.) control the rate of reactions and regulate cell processes D.) build tissues such as bone and muscle

26. Which element is found in proteins but not carbohydrates or lipids? A.) C B.) N C.) H D.) O

27. Amino acids are the building blocks of which macromolecule? A.) carbohydrate B.) lipid C.) DNA D.) protein

28. An organism’s genetic information is stored in which type of macromolecule? A.) DNA (nucleic acid) B.) lipid C.) carbohydrate D.) protein