a. Which of the following is expected to be paramagnetic: Ne, Li2, Li2+, N2, N2+, N22−? b. For each of the substances in part (a) that is paramagnetic, determine the number of unpaired electrons it has.

Verified step by step guidance

1. Identify the electronic configuration of each species: Ne, Li_2, Li_2^+, N_2, N_2^+, N_2^{2−}.
2. Use molecular orbital theory to determine the electron configuration for each diatomic molecule or ion.
3. Determine the presence of unpaired electrons in the molecular orbitals for each species.
4. Identify which species have unpaired electrons, as these will be paramagnetic.
5. Count the number of unpaired electrons for each paramagnetic species.

Key Concepts

Paramagnetism

Paramagnetism is a property of materials that are attracted to magnetic fields due to the presence of unpaired electrons in their atomic or molecular orbitals. When an atom or molecule has one or more unpaired electrons, it exhibits a net magnetic moment, allowing it to align with an external magnetic field. In contrast, materials with all electrons paired are typically diamagnetic and are repelled by magnetic fields.

Electron Configuration

Electron configuration describes the distribution of electrons in an atom or molecule's orbitals. It is essential for determining the number of unpaired electrons, which directly influences paramagnetic behavior. The Aufbau principle, Hund's rule, and the Pauli exclusion principle guide the filling of orbitals, helping to predict the magnetic properties of various substances.

Molecular Orbital Theory

Molecular Orbital Theory (MOT) provides a framework for understanding the electronic structure of molecules by combining atomic orbitals to form molecular orbitals. These orbitals can be occupied by electrons and can be either bonding or antibonding. MOT is particularly useful for predicting the magnetic properties of diatomic molecules, as it allows for the identification of unpaired electrons in molecular orbitals, which is crucial for determining paramagnetism.