Answer:
It is important to note that iron, cobalt, and nickel which appear in period 4, of the transition metals, next to each other, share very similar physical and chemical properties and are known collectively as the iron triad
The comparison of the properties of iron includes
Chemical properties
1) Atomic number; The atomic number of iron is 26 while the atomic number of nickel is 28
2) The oxidation states of iron are 2, 3, 6 while the oxidation state of nickel are 2,3
3) The ionization energies in kJ/mol are first 759, second 1561, and third 2957 for iron and first 737, second 1753, and third 3393 for nickel
Physical properties
1) The mass of iron is 55.85 with density = 7.87 g/cm³, the mass of nickel is 58.69 with density = 8.91 g/cm³
2) The melting point of iron is 1530°C, boiling point 2862°C and that of nickel are 1455°C and 2732°C
3) The electrical conductivity of iron is 16 and that of nickel is 23
Explanation: