Which of the following ions will be attracted to a magnetic field?

• A. Mg^{2+}
• B. Fe^{3+}
• C. Na^{+}
• D. Zn^{2+}

Answer: (B)

Verified step by step guidance

1. Understand that ions are attracted to a magnetic field if they are paramagnetic, meaning they have unpaired electrons.
2. Recall that Mg^{2+}, Na^{+}, and Zn^{2+} ions typically have all their electrons paired, making them diamagnetic and not attracted to a magnetic field.
3. Recognize that Fe^{3+} ion has unpaired electrons in its d-orbitals, which makes it paramagnetic and attracted to a magnetic field.
4. Use the electron configuration of Fe^{3+} to confirm the presence of unpaired electrons: Fe has atomic number 26, so Fe^{3+} has 23 electrons, leading to unpaired electrons in the 3d subshell.
5. Conclude that among the given ions, only Fe^{3+} is paramagnetic and will be attracted to a magnetic field.