Question

The first-row transition metals from chromium through zinc all have some biologic function in the human body. How many unpaired electrons are present in each of these first-row transition metals in the ground state?

Short answer

The number of unpaired electrons in the ground state for the first-row transition metals from chromium to zinc are: Cr (5), Mn (5), Fe (4), Co (3), Ni (2), Cu (1), and Zn (0).

Step-by-step solution

Identify the atomic number of the elements

The elements are chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn). Their atomic numbers are: Cr (24), Mn (25), Fe (26), Co (27), Ni (28), Cu (29), Zn (30).

Write the electronic configuration

Electronic configurations of these elements in the ground state are: - Cr (\(Z = 24\)): \(1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^1\) - Mn (\(Z = 25\)): \(1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^2\) - Fe (\(Z = 26\)): \(1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 4s^2\) - Co (\(Z = 27\)): \(1s^2 2s^2 2p^6 3s^2 3p^6 3d^7 4s^2\) - Ni (\(Z = 28\)): \(1s^2 2s^2 2p^6 3s^2 3p^6 3d^8 4s^2\) - Cu (\(Z = 29\)): \(1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^1\) - Zn (\(Z = 30\)): \(1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2\)

Determine the number of unpaired electrons

To find the number of unpaired electrons, we need to count the number of electrons in the partially filled orbitals: - Cr: 3d orbital has 5 unpaired electrons. - Mn: 3d orbital has 5 unpaired electrons. - Fe: 3d orbital has 4 unpaired electrons. - Co: 3d orbital has 3 unpaired electrons. - Ni: 3d orbital has 2 unpaired electrons. - Cu: 3d orbital is fully filled and only the 4s orbital has 1 unpaired electron. - Zn: All orbitals are fully filled, so there are no unpaired electrons. So, the number of unpaired electrons in the ground state for the first-row transition metals from chromium to zinc are 5, 5, 4, 3, 2, 1, and 0, respectively.