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:
Mercury exist as liquid at normal earth tempertures
56km/s is 201600m/hr to its equivalent.
11. ionic charge +1, helium.
12. ionic charge 2-, neon.
13. ionic charge 3+, neon.
