because the gas particles are forced closer together.
Calcium Floride (Caf2)
Hope this helped =D
Answer:
Because the most common form of Nickel is Ni-58 while the most common form of Cobalt is Co-59, this means that Cobalt (which is number 27 on the periodic table) has 27 protons and 32 neutrons. Therefore 1 less proton but 2 more neutrons and hence has a greater mass than Nickel.
Explanation: