The Chemical Basis of Life

. The four most abundant elements in the human body are A. carbon, hydrogen, oxygen, and iron. B. carbon, hydrogen, oxygen, and nitrogen. C. calcium, hydrogen, sodium, and potassium. D. carbon, oxygen, magnesium, and zinc. E. carbon, sulfur, calcium, and potassium. 2. The smallest particle of an element that still exhibits the chemical characteristics of that element is a(n) A. electron. B. atom. C. chemical bond. D. orbital. E. proton. 3. Subatomic particles located around the nucleus of an atom are A. protons. B. electrons. C. neutrons. D. neutrinos. E. photons. 4. A neutral atom contains A. more protons than electrons. B. more electrons than protons. C. the same number of electrons and protons. D. only neutrons. E. None of these choices is correct. 5. Which of the following best describes a proton? A. one negative charge, no mass, found in orbitals B. no charge, mass of one, found in nucleus C. one positive charge, mass of one, found in nucleus D. subatomic particle with no electric charge E. None of these choices is correct. clean A 6. The mass number of an atom is the number of A. protons in the atom. B. neutrons in the atom. C. protons plus electrons in the atom. D. electrons plus neutrons in the atom. E. neutrons plus protons in the atom. 7. An atom has an atomic number of 19 and a mass number of 39. This atom will have A. 19 neutrons. B. 20 neutrons. C. 39 neutrons. D. 58 neutrons. E. 20 electrons. 8. An atom of chlorine has 17 protons and 18 neutrons. Which of the following statements is true? A. Chlorine atoms have 18 electrons. B. Chlorine has a mass number of 35. C. Chlorine has an atomic number of 18. D. Chlorine has 35 electrons. E. Chlorine has an atomic number of 35. 9. Isotopes of the same element have A. the same number of neutrons but different numbers of protons. B. different numbers of protons and electrons. C. the same mass number. D. the same atomic number but differ in their mass numbers. E. no mass number. 10. The amount of matter in an object is its A. mass. B. weight. C. density. D. volume. E. size. 11. The number of atoms in exactly 12 grams of carbon-12 is called A. Dalton's number. B. Socrates's number. C. Avogadro's number. D. Pasteur's number. E. Le Chatelier's number. 12. Electrons A. comprise the majority of the mass of an atom. B. are located in the nucleus of an atom. C. have a positive charge of one. D. are the subatomic particles most involved in bonding behavior of atoms. E. do not participate in the bonding of atoms. 13. A neutral atom will become a cation if it A. gains electrons. B. gains protons. C. loses electrons. D. loses protons. E. gains neutrons. 14. In ionic bonding, A. only non-polar molecules are involved. B. a "sea of electrons" forms. C. electrons are transferred from one atom to another. D. two hydrogen atoms share one pair of electrons. E. the charge of the ion does not play a role in the bond. 15. Covalent bonds form when A. atomic nuclei fuse. B. molecules become ionized. C. neutrons are transferred from one atom to another. D. protons are lost from atoms. E. electrons are shared between two atoms. 16. Molecules that form when electrons are shared unequally between atoms are called A. salt molecules. B. polar molecules. C. nonpolar molecules. D. lopsided molecules. E. None of these choices are correct.