Electron Configuration and Atomic Orbitals (ORCHEM.pdf)
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University of Negros Occidental – Recoletos
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Summary
This document provides a comprehensive overview of electron configuration, atomic orbitals, including s, p, d, and f orbitals. It also explores concepts like hybridization, sigma and pi bonds, and the Aufbau principle. The document is a useful resource for understanding fundamental chemistry concepts and can aid in the study of bonding.
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# Electron Configuration - Electron configuration describes how electrons are distributed in atomic orbitals. ## Orbitals - The orbital represents the space where an electron is mostly found. - There are four kinds of orbitals: s, p, d, and f. ### Types of Orbitals - **s orbitals:** are spherical...
# Electron Configuration - Electron configuration describes how electrons are distributed in atomic orbitals. ## Orbitals - The orbital represents the space where an electron is mostly found. - There are four kinds of orbitals: s, p, d, and f. ### Types of Orbitals - **s orbitals:** are spherical shaped. - **p orbitals:** are dumbbell shaped. - **d orbitals:** are clover shaped. - **f orbitals:** are more complex in shape. ## Atomic Orbitals - **s orbital** - a single spherical shape. - **p orbitals** - three p orbitals oriented along the x, y, and z axes. - **d orbitals** - five d orbitals, with complex shapes. - **f orbitals** - seven f orbitals, with even more complex shapes. ## Orbitals and Electron Capacity | Principal energy level (n) | Type of sublevel | Number of orbitals per type | Number of orbitals per level (n²) | Maximum number of electrons (2n²) | |:---:|:---:|:---:|:---:|:---:| | 1 | s | 1 | 1 | 2 | | 2 | s | 1 | 4 | 8 | | | p | 3 | | | | 3 | s | 1 | 9 | 18 | | | p | 3 | | | | | d | 5 | | | | 4 | s | 1 | 16 | 32 | | | p | 3 | | | | | d | 5 | | | | | f | 7 | | | ## Aufbau Principle - Named after the German word "Aufbeen", meaning "build-up". - Dictates that electrons will occupy the orbitals having lower energies, before occupying higher energy orbitals. ## Writing of Electron Configuration - **He 1s<sup>2</sup>** - The number before the orbital letter (1 in this example) indicates the energy level. ## Pauli Exclusion Principle - States that a maximum of two electrons can fit in an orbital. - These two electrons must have opposite spins (spin up and spin down). - States that no two atoms have the same values for all quantum numbers. ## Ionic Bond - Formed because of the attraction between ions. - This is commonly formed between a metal and a non-metal. ## Covalent Bond - Involves sharing of electrons because both elements have high electronegativities. - This is usually between two non-metals. ## Valence Bond Theory - A covalent bond forms when an atomic orbital from one atom overlaps with an atomic orbital from the other atom. ## Hybridization - The mixture of orbitals at the same energy level. - This shows the molecular geometry and the bonding of the atomic orbitals. ### - sp<sup>3</sup> hybrid orbitals - s + p + p + p - 25 % s and 75 % p - Four sp<sup>3</sup> hybridized orbitals. - They are tetrahedral in shape, with bond angles of approximately 109.5°. - Common in molecules like methane (CH<sub>4</sub>), where the carbon atom forms four single bonds with four hydrogen atoms. ### - sp<sup>2</sup> hybrid orbitals - s + p + p - 33 % s and 67 % p - Three sp<sup>2</sup> hybridized orbitals. - They are trigonal planar in shape, with bond angles of approximately 120°. - Common in molecules like ethene (C<sub>2</sub>H<sub>4</sub>), where the carbon atom forms three sigma bonds and one pi bond. ### - sp hybrid orbitals - s + p - 50 % s and 50 % p - Two sp hybridized orbitals and two unhybridized orbitals. - They are linear in shape, with bond angles of approximately 180°. - Common in molecules like ethyne (C<sub>2</sub>H<sub>2</sub>) where the carbon atom forms two sigma bonds and two pi bonds. ## Sigma Bonds - Formed by head-to-head overlapping of atomic orbitals. - Strong covalent bond. ## Pi Bonds - Formed by sideways overlapping of atomic orbitals. - Weaker covalent bond.
