Why is cobalt placed before nickel on the periodic table of the elements?

Answer 1

Cobalt comes first because it has fewer protons (27) and nickel has more (28). The Atomic Mass is not important in the modern Periodic Table (but that's all they knew in Mendeleev's day).

The reason cobalt is heavier is because it has more NEUTRONS (32).

Answer 2

Atomic mass isn't actually very important in organizing the periodic table. It all goes by the atomic number, or, the number of electrons in an element. If you make the choice to learn about orbitals, you'll find the pattern;

1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f146d107p6

If you go through all those electron configurations, you'll get the modern periodic table.

We have E1-E116 and E118. E117 was not a reproducible result, and was debunked as an actual discovery. We know E117 is out there, we just don't know how to make it yet.

Answer 3

Cobalt is placed before nickel on the periodic table because elements are arranged by increasing atomic number. Cobalt has an atomic number of 27, while nickel has an atomic number of 28. Therefore, cobalt comes before nickel based on their atomic numbers.

Answer 4

Cobalt is placed before Nickel because Cobalt has less protons than Nickel.

Answer 5

Nickel has a lower atomic mass than cobalt.

Answer 6

cobalt has 27 protons, nickel has 28