The atomic number of an element is determined by its total number of a protons only b neutrons only c electrons only d protons plus neutrons e protons plus electrons 17. The atomic mass of an element is equal to the number of a protons only b neutrons only c electrons only d protons plus neutrons e protons plus electrons 18. The maximum number of electrons that can be held in the K and L energy levels are a 2 and 4, respectively b 8 and 6, respectively c 4 and 8, respectively d 2 and 8, respectively 20. Ordinary carbon has 12 protons and 12 neutrons. Another form of carbon has 2 extra neutrons.
All atoms tend to fill their outer energy levels with the maximum number of electrons.
During oxidation, molecules a disintegrate b gain neutrons c lose electrons d lose carbon e are converted to oxygen atoms 28. Because the electrons are not shared equally in a water molecule, and the electrons spend more time around the oxygen, water is a hydrophobic b only negatively charged c ionic d only positively charged e polar 29. Animals store glucose in the form of a amylose b glycogen c glycerol d guanine e cellulose 32. Complex carbohydrates are polymers formed of structural units called a starches b fatty acids c nucleic acids d phosphate groups e monosaccharides 38. In nucleic acids, the purine nitrogenous bases are a uracil and thymine b cytosine and guanine c thymine and cytosine d adenine and guanine e guanine and thymine 39.