In the previous article, we explored the basic components of an atom and how they contribute to its overall structure. Now, let's dive deeper into electron configurations and the fascinating world of periodic trends.

Electron Configurations: Electron configurations provide insight into how electrons are distributed within different energy levels and orbitals around the nucleus. The aufbau principle states that electrons fill the lowest energy levels first. Hund's rule dictates that electrons occupy orbitals of the same energy level singly before pairing up. Lastly, the Pauli exclusion principle states that no two electrons can have the same set of quantum numbers.

Example: For the element carbon (C), the electron configuration is 1s² 2s² 2p². This means that the first energy level (1s) contains two electrons, the second energy level (2s) contains two electrons, and the second energy level (2p) contains two electrons in separate orbitals.

Periodic Trends: Understanding electron configurations allows us to analyze periodic trends, which are patterns observed in the properties of elements as you move across or down the periodic table.

Example 1: Ionization energy refers to the energy required to remove an electron from an atom. Generally, ionization energy increases from left to right across a period and decreases from top to bottom within a group. This is because electrons in higher energy levels experience less attraction from the positively charged nucleus, making them easier to remove.

Example 2: Atomic radius refers to the size of an atom. As we move across a period, atomic radius decreases. This is because electrons are added to the same energy level while the nuclear charge increases, resulting in stronger attraction and a more tightly held outer shell.

Tags: [electron configurations, periodic trends, aufbau principle]