Use the periodic table to determine each quantity. a. the number of 2s electrons in Li

Key Concepts

Periodic Table

The periodic table is a systematic arrangement of elements based on their atomic number, electron configuration, and recurring chemical properties. It provides essential information about each element, including its position, which helps in understanding its electron structure and reactivity. Elements are organized into periods and groups, with similar properties found in the same columns.

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. For lithium (Li), with an atomic number of 3, the electron configuration is 1s² 2s¹, indicating that it has two electrons in the 1s orbital and one in the 2s orbital.

Valence Electrons

Valence electrons are the electrons in the outermost shell of an atom and are crucial for determining an element's chemical properties and reactivity. In the case of lithium, the 2s electron is a valence electron, which plays a significant role in bonding and chemical reactions. Understanding the number of valence electrons helps predict how an element will interact with others.