Question

biology study quiz 1. atoms and molecules: the chemical basis of life multiple choice 1. an organic compound differs from an inorganic compound in that an organic compound a. contains carbon. b. contains two or more atoms. c. lacks valence electrons. d. lacks isotopes. e. is basic rather than acidic. 2. an element is defined as a substance that a. is composed of more than one kind of atom. b. is held together by covalent bonds. c. cannot be broken into simpler substances by chemical reactions. d. cannot burn. e. is soluble in both acid and base. 3. the particular type of element is determined by the number of a. electrons b. protons c. neutrons d. valence electrons e. energy levels 4. the difference between a stable isotope and a radioisotope is that: a. the stable isotope emits radiation. b. the radioisotope emits radiation. c. the stable isotope emits light. d. the stable isotope absorbs radiation. e. the radioisotope has an unequal number of protons and electrons. 5. isotopes differ from each other with respect to the number of: a. protons only. b. electrons only c. neutrons only. d. both protons and electrons. e. both neutrons and protons. 6. the chemical behavior of an atom is determined by most directly by the: a. atomic number. b. atomic weight. c. number of energy levels. d. number of valence electrons. e. number of neutrons. 7. chlorine has seven electrons in its valence shell. the number of electrons it must gain to complete its valence shell is a. one

Explanation:

1. Organic compounds contain carbon, distinguishing them from inorganic compounds.
2. An element is a substance that cannot be broken into simpler substances by chemical reactions.
3. The number of protons determines the type of element.
4. Radioisotopes emit radiation while stable isotopes do not.
5. Isotopes differ in the number of neutrons.
6. The chemical behavior of an atom is most directly determined by the number of valence electrons.
7. Chlorine needs to gain one electron to complete its valence shell as it has 7 valence - electrons and a full valence shell has 8 electrons.

Answer:

1. a. contains carbon
2. c. cannot be broken into simpler substances by chemical reactions
3. b. protons
4. b. the radioisotope emits radiation
5. c. neutrons only
6. d. number of valence electrons
7. a. one