12: The atomic number of an element is the number at the very top, so potassium's atomic number would be 19, and Krypton's atomic number would be 36.
13: The atomic number is, by definition, the number of protons in the nucleus of an atom, so the atom with the greater atomic number has more neutrons in its nucleus. In this case, it is Krypton (36 protons).
14: Potassium (K) is in the first group (column) on the periodic table, so we call it group 1A or the "Alkali Metals". Krypton is in the 18th group (column) of the periodic table or group 8A (not 18A), called the "Noble Gases".
