Symbol Name 17C 13C 22Ne 345 Ca Kr 94Zr carbon-12 carbon-13 neon-22 neon-21 sulfur-34 chlorine-37 krypton-82 zirconium-94 Zn 672n 56Fe 55Mn 42Ca2+ 1271 lodine-127 zinc-67 manganese-55 Isotopes - worksheet. Insert missing numbers into table. Atomic # Mass # # of protons 6 6 6 10 10 20 17 40 30 25 232 12 13 34 44 82 6 10 16 20 30 20 53 # of neutrons 6 12 11 20 46 54 36 # of electrons 6 10 10 16 20 40 30 Atomic mass=% of isotope 1 x mass of isotope 1+% of isotope 2 x mass of isotope 2+.... (% of isotope must be converted to decimals) 1. Argon has three naturally occurring isotopes: argon-36, argon-38, and argon-40. Based on argon's reported atomic mass (found in periodic table), which isotope is the most abundant in nature? 2. Rubidium has two common isotopes 85Rb and 7Rb.If the abundance of 25 Rb is 72.2% and abundance of 7 Rb is 27.8%, calculate the average atomic mass of rubidium. 3. Naturally occurring chlorine is 75.53% of 35Cl (34.969 amu) and rest of it is 7 Cl (36.996 amu). Calculate average atomic mass of chlorine. 4. Titanium has five common isotopes: titanium-46 (8.0%), titanium-47 (7.8%), titanium-48 (73.4%), titanium-49 (5.5%), and titanium-50 (5.3%). What is the average atomic mass of titanium?