Why is nickel located to the right of cobalt on the periodic table? a) nickel has one more proton than colbalt b) cobalt has one more neutron than nickel c) colbalt has a smaller atomic radius than nickel d) nickel has a smaller mass number than cobalt

The correct option is A.
The periodic table is a table of all known elements. The elements in the periodic table are arranged on the basis of their atomic numbers. The atomic number is determined by the number of proton that an element has; the elements are arranged in order of increasing order of atomic number. Thus, nickel is located to the right of  cobalt on the periodic table because nickel has one more proton than cobalt. 

The reason to why is nickel located to the right of cobalt on the periodic table is that A) nickel has one more proton than cobalt. We know that as the periodic table of elements moves from left to right, there is an increase of protons so Nickel has more protons because it is located at the right side of cobalt.

Sorry i dont understand the question can you rephase it?