The element Niobium (Z=41) is a transitional metal. It has two valences 3+ and 5+. Using an orbital filling diagram, predict the order in which electrons will leave their orbitals in order to achieve those valences (i.e. the first ___ electron will come out of the ___ orbital).

The electron configuration is [Kr] 4d4 5s1

The +5 state would be the removal of the 4-4d electrons plus the 1 5s electron. The +3 is the removal of the 5s1 electron plus two of the others.

To predict the order in which electrons will leave their orbitals in order to achieve the valences of Niobium (Z=41), we need to understand the electron configuration of niobium and its orbital filling diagram.

The electron configuration of niobium can be determined by using the Aufbau principle and the periodic table. The Aufbau principle states that electrons occupy the lowest energy orbitals available first.

In the case of Niobium (Z=41), the electron configuration is [Kr] 4d^4 5s^1.

Let's now draw the orbital filling diagram step by step:

1. Start with the electron configuration of the noble gas before niobium, which is krypton (Kr) with the electron configuration [Kr] = 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6.

2. Proceed to fill the 4d orbitals. Since niobium has 4d^4, we will fill four 4d orbitals with a total of 8 electrons:

4d: ↑↓ ↑↓ ↑↓ ↑

3. Finally, fill the 5s orbital with one electron:

5s: ↑

Now, to achieve the valences of 3+ and 5+ for niobium, we need to remove electrons from the highest energy levels first. In this case, the 5s orbital will lose the single electron first to achieve a 3+ valence, resulting in the configuration [Kr] 4d^4.

For a 5+ valence, the five valence electrons will be removed from the 4d orbitals, starting from the highest energy level:

4d: ↑↓ ↑↓ ↑↓ ↑

Therefore, the order in which electrons will leave their orbitals to achieve the valences of niobium is:

To achieve 3+ valence: First, the electron will come out of the 5s orbital.
To achieve 5+ valence: The first electron will come out of the 4d orbital.

It is important to note that electron configurations and valence states may vary depending on the chemical environment and bonding of the element.