Electronic Structure of Atoms

Electronic Structure of Atoms

Basic Concepts

• An atom’s electronic structure is comprised of a central nucleus surrounded by electrons in ‘shells’ or ‘energy levels’
• The nucleus consists of protons and neutrons, while electrons inhabit areas around the nucleus
• Each electron shell can hold a certain number of electrons - the innermost shell can hold up to 2, the second can hold up to 8, and so on

Periodic Table and Electronic Structure

• Rows on the Periodic Table correspond to the number of shells an atom has
• The position of an element in the Periodic Table tells us about its electronic structure
• Groups in the Periodic Table (columns) indicate the number of electrons in the outer shell

Electron Configuration

• Electron configuration is the distribution of electrons among the orbitals of an atom
• Configurations often follow a ‘2, 8, 8’ rule but there are exceptions such as copper and chromium
• The electron configuration of an atom can be represented using an electron configuration diagram or an electron configuration notation

Energy Levels

• Each electron shell represents a different energy level - the outermost shells have higher energy than the shells closer to the nucleus
• Electrons can move between these energy levels by absorbing or releasing energy

Valence Electrons

• Valence electrons are the electrons in the outermost shell of an atom
• The number of valence electrons dictates the chemical properties and reactivity of the element as they are involved in chemical bonding

Ionic and Covalent Bonding

• When atoms lose or gain electrons to achieve a full outer electron shell, they form ionic bonds
• Covalent bonds are formed when atoms share electrons to achieve full outer shells

Remember, understanding the electronic structure of atoms forms the backbone to understanding chemical reactions and interactions.