The following do not represent valid ground-state electron configurations for an atom either because they violate the Pauli exclusion principle or because orbitals are not filled in order of increasing energy. Indicate which of these two principles is violated in each example. (b) 3Xe46s3

Verified step by step guidance

1. Identify the electron configuration given: 3Xe46s3.
2. Recognize that '3Xe' likely refers to the electron configuration of Xenon (Xe), which should be written as '[Xe]'.
3. Understand that '[Xe]' represents the noble gas configuration up to the 5p orbital, which is fully filled.
4. Analyze the configuration '46s3'. The correct notation should be '6s^3'. However, the 's' orbital can hold a maximum of 2 electrons, not 3.
5. Conclude that the principle violated here is the Pauli exclusion principle, which states that no two electrons in an atom can have the same set of four quantum numbers. Here, attempting to place three electrons in the '6s' orbital, which can only hold two, violates this principle.

Key Concepts

Pauli Exclusion Principle

The Pauli Exclusion Principle states that no two electrons in an atom can have the same set of four quantum numbers. This means that each electron must occupy a unique state within an atom, which prevents any two electrons from being in the same orbital with the same spin. Violating this principle results in an invalid electron configuration.

Aufbau Principle

The Aufbau Principle describes the order in which electrons fill atomic orbitals. According to this principle, electrons occupy the lowest energy orbitals first before moving to higher energy levels. If an electron configuration shows orbitals filled out of this order, it violates the Aufbau Principle, leading to an incorrect representation of the atom's electron structure.

Electron Configuration Notation

Electron configuration notation is a way to represent the distribution of electrons in an atom's orbitals. It uses a series of numbers and letters to indicate the energy levels and types of orbitals occupied by electrons. Understanding this notation is crucial for identifying whether a given configuration adheres to the established principles of quantum mechanics, such as the Pauli Exclusion Principle and the Aufbau Principle.