The highest oxidation state for the early transition metals Sc, Ti, V, Cr, and Mn is the periodic group number. The highest oxidation state for the later transition elements Fe, Co, and Ni is less than the periodic group number. Explain.

Video transcript

All right. Hi Yvonne. So this question says true or false as we move from early to later transition metals like from Scandium to nickel, the energy difference between 3d and four S orbitals increases causing the later transition metals to typically exhibit oxidation states below their group numbers. So for this question, let's go ahead and recall the concept of effective nuclear charge or Z affected in which the Z effective refers to the effective positive charge of a given nucleus. And it's also worth noting in this case that Scandium and nickel happened to fall in the same role or on the same period in the periodic table, they're both transition metals and scandium is farther to the left side. Whereas nickel is farther to the right side. Now as we move across a period, right or from left to right, in this case, from Scandium towards nickel, then the effective nuclear charge is actually going to increase. And the reason for this is because the atomic number, therefore, the number of protons also increases resulting in consistent shielding by the inner electrons. Now, when it comes to the earlier transition metals, then there is a relatively small energy difference between 3d and four S orbitals, which means that 3d and for as orbitals are both going to be involved in bonding when it comes to the early transition metals. Now, as we go from the early transition metals to the later transition metals, then the effective nuclear charge is also going to increase. So as the effective nuclear charge increases, right, the 3d orbitals are going to be more stable relative to four S orbitals. And the reason for this is because as the effective nuclear charge increases these 3d orbitals are pulled closer towards the nucleus. So therefore, right, as the 3d orbitals or the electrons in 3d orbitals become more stable as a result of this trend, then that means that generally speaking, they're going to be harder to remove, right, due to this enhanced stability. And because of this right, later transition metals do often exhibit or oxidation states, excuse me below their actual group numbers. So all this is to say that the statement proposed in the text of the question is actually true, right. Later transition metals typically exhibit oxidation states below their group numbers due to the enhanced stability of electrons in 3d orbitals compared to four S orbitals. So with that being said, thank you very much for watching and I hope we found this helpful.