Chemical Reaction : Ca+2 + 2Br- ---- CaBr2
The answer: LEO is Bromine (Br-1); the oxidation state changes from (0 to -1) and GER is Calcium (Ca+2); the oxidation state changes from (0 to +2).
Atomic mass is found by adding the number of protons + number of neutrons, as their atomic weights are both 1 atomic mass unit (amu). The Atomic number is the number of protons only. If gold has an atomic mass of 198, subtract the atomic number (79) to find number of neutrons: 198-79=119 neutrons
