Write the electron configurations for the following ions, and determine which have noble-gas configurations: (a) Ti2+ (b) Br- (c) Mg2+ (d) Po2- (e) Pt2+ (f) V3+

Verified step by step guidance

1. Identify the atomic number of each element from the periodic table. This will tell you the number of electrons in the neutral atom.
2. Adjust the number of electrons based on the charge of the ion. For cations (positive charge), subtract electrons; for anions (negative charge), add electrons.
3. Write the electron configuration for each ion using the adjusted electron count. Start filling from the lowest energy orbital (1s) and move to higher energy orbitals (2s, 2p, 3s, etc.) following the Aufbau principle, Hund's rule, and the Pauli exclusion principle.
4. Compare the electron configuration of each ion to the nearest noble gas configuration. Noble gases have complete outer shells, which generally means filled s and p orbitals in their highest occupied energy level.
5. Determine which ions have noble-gas configurations by checking if their electron configurations match exactly with that of any noble gas (He, Ne, Ar, Kr, Xe, Rn).

Key Concepts

Electron Configuration

Electron configuration describes the distribution of electrons in an atom's orbitals. It follows the Aufbau principle, which states that electrons fill the lowest energy orbitals first, and is represented using a notation that indicates the energy levels and sublevels occupied by electrons. Understanding how to write electron configurations is essential for predicting the chemical behavior of elements and their ions.

Ionic Charge and Electron Loss/Gain

Ionic charge refers to the net electrical charge an atom has after losing or gaining electrons to form an ion. For cations, such as Ti2+ and Mg2+, electrons are lost, resulting in a positive charge, while anions, like Br-, gain electrons, leading to a negative charge. Recognizing how to adjust the electron configuration based on the ionic charge is crucial for determining the final electron arrangement.

Noble-Gas Configuration

Noble-gas configuration is a shorthand notation for electron configurations that reflects the stable electron arrangement of noble gases, which have full outer electron shells. Atoms and ions that achieve this configuration are typically more stable and less reactive. Identifying whether an ion has a noble-gas configuration helps in understanding its stability and reactivity in chemical reactions.