Reading the periodic table

This task is about using part of the periodic table to answer questions.
 Use the information from this section of the Periodic Table to answer the following questions.

Question Change answer

a)  Select the element whose atom has the greatest mass.

Question Change answer

b)  Select the metal which has atoms that are almost twice the mass of nickel atoms.

Question 2Change answer

c)  How many electrons does one atom of silver have?  

Question 2Change answer

d)  Cobalt is an element in Group 9, and is in the same row as nickel, copper, and zinc.
     What is cobalt's atomic number?