33. Elements differ according to the number of protons their atoms contain, a value called the element's atomic number. All atoms of a given element have the same number of protons and an equal number of electrons. The number of neutrons in an atom is not predictable but is generally as great or greater than the number of protons.

The total number of protons plus neutrons in an atom is called the atom's mass number. 40. Protons, electrons, and neutrons. Protons, neutrons (1 amu) and electrons 5 x 10-4. Protons have a positive charge, neutrons have no charge, and electrons have a negative charge. 41.

The protons and neutrons are packed inside the nucleus and the electrons are outside of the nucleus forming an electron cloud. 43. (a) Phosphorus P (b) Niobium Nb (c) Cobalt Co 45. (a) protons = 13, electrons = 13, neutrons = 14 (b) protons = 14, electrons = 14, neutrons = 14 (c) protons = 5, electrons = 5. , neutrons = 6 (d) protons = 47, electrons = 47, neutrons = 68 46. C 49.

(a) 122 (b) 136 (c) 118 (d) 48 51. (a) Neon (Ne) (b) Vanadium (V) (c) Iron (Fe) 54. 60. (a) Metals (b) Transition metal element (c) 3 d 62. Selenium 66. Each orbital can hold only TWO electrons, which must be of opposite spin.

70. There are 10 electrons that are present in this atom. This element is NEON. 71. There are 14 electrons that are present in this atom. This element is SILICON.

73. (a) (b) (c) (d) 75. Four because the group numbers from 1 A through 8 A give the numbers of valence electrons for the elements in each main group. 77. Group 6 A 79. 83.

The stars underwent a gravitational collapse resulting in the synthesis of elements heavier than iron. 84. (a) ultraviolet (b) Gamma waves (c) X-rays 85. Ultraviolet rays have a higher concentrated energy than visible light, which makes their wavelength shorter and more powerful.