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This is the complete lecture note for CHM 214 Structure and Bonding. You can read it online below, open it in the full viewer, or download the PDF for offline study. It pairs with the course's video lectures, so you can read and watch together.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS • Course code: CHM 214 • Course title: Structure and Bonding • Course credit load: 2 Units (C: LH 30) • Series titles: Quantum States, Orbitals, Shape and Energy Valence Theory, Electron Repulsion and Atomic Spectra Symmetry, Molecular Geometry and Molecular Orbital Theory Methods of Determining Molecular Shape, Bond Lengths and Angles Structure and Chemistry of Representative Main Group Compound Suggested Outline Part 1: Concept of Quantum States Sub-Part 1.1: Definition of quantum states Sub-Part 1.2: Energy levels and quantisation Sub-Part 1.3: Significance in atomic structure Part 2: Atomic Orbitals Sub-Part 2.1: Definition and shapes of orbitals Sub-Part 2.2: Types of orbitals (s, p, d, f) Sub-Part 2.3: Orbital energy ordering Part 3: Orbital Shapes and Orientation Sub-Part 3.1: Visualising orbital shapes Sub-Part 3.2: Spatial orientation and nodal planes Sub-Part 3.3: Implications for bonding Part 4: Energy Considerations in Orbitals Sub-Part 4.1: Relative energies of orbitals Sub-Part 4.2: Factors affecting orbital energy (n, l values) Sub-Part 4.3: Applications in predicting chemical behaviour
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Series Learning Outcomes Upon completing this Series, you should be able to: SLO 1.1 define quantum states and explain their significance in atomic structure, SLO 1.2 describe the shapes and characteristics of atomic orbitals, SLO 1.3 illustrate orbital orientation and nodal planes with examples, SLO 1.4 analyse the relative energies of orbitals and the factors that influence them, and SLO 1.5 apply knowledge of orbital energy considerations to predict chemical behaviour. Introduction The study of quantum states and orbitals forms the foundation of modern chemistry. Atoms and molecules behave in ways that cannot be explained by classical physics alone, and it is through quantum theory that we understand their structure, energy, and bonding. This Series introduces you to the essential concepts of quantum states, orbitals, their shapes, and the energy considerations that govern chemical behaviour. By engaging with these ideas, you will gain a deeper appreciation of how atomic structure underpins the entire discipline of chemistry. The aim of this Series is to equip you with the knowledge and skills to define quantum states, describe orbital shapes and orientations, and analyse how energy levels influence chemical bonding and reactivity. We shall commence this Series by examining the concept of quantum states, focusing on their definition, energy levels, and significance in atomic structure. Next, we will explore atomic orbitals, considering their shapes, types, and energy ordering. Following that, we will move on to orbital shapes and orientation, where you will learn how spatial features and nodal planes affect bonding. Finally, we will conclude with energy considerations in orbitals, analysing relative energies and the factors that influence them, while also highlighting their applications in predicting chemical behaviour. 1.1 Concept of Quantum States 1.1.1 Definition of quantum states A quantum state is a description of the condition of an electron in an atom, defined by a set of quantum numbers that specify its energy, position, and spin. These quantum numbers include the principal quantum number (n), the azimuthal quantum number (l), the magnetic quantum number (m), and the spin quantum number (s). Together, they provide a complete picture of the electron’s behaviour within the atom. Fill in the blank: The quantum number that defines the main energy level of an electron is called the __________________ quantum number.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Figure 1.1: Quantum numbers defining an electron’s quantum state 1.1.2 Energy levels and quantisation Quantisation means that electrons can only occupy specific energy levels, not values in between. These levels are determined by the principal quantum number (n). When electrons absorb or release energy, they move between these discrete levels, producing phenomena such as atomic spectra. This explains why atoms emit or absorb light at characteristic wavelengths. Fill in the blank: The idea that electrons can only occupy specific energy levels is known as __________________. Plate 1.1: Electron transitions in quantised energy levels
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 1.1.3 Significance in atomic structure Quantum states explain why electrons are arranged in shells and subshells, which in turn determine the chemical properties of elements. The arrangement of electrons, known as the electronic configuration, dictates how atoms bond and interact with one another. This makes quantum states fundamental to understanding atomic structure and chemical behaviour. Fill in the blank: The arrangement of electrons in shells and subshells within an atom is called the __________________ configuration. Box 1.1: Importance of quantum states in chemistry Determine electron arrangement in atoms Explain chemical bonding and reactivity Predict magnetic and optical properties Provide basis for periodic trends Pilot questions 1.1 The quantum number that defines the main energy level of an electron is called the: A. Spin quantum number B. Principal quantum number C. Magnetic quantum number D. Azimuthal quantum number (Linked to SLO 1.1) The idea that electrons can only occupy specific energy levels is known as: A. Quantisation B. Magnetisation C. Ionisation
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS D. Excitation (Linked to SLO 1.1) The arrangement of electrons in shells and subshells within an atom is called the: A. Orbital diagram B. Electronic configuration C. Quantum state D. Energy distribution (Linked to SLO 1.1) Which quantum number specifies the orientation of an orbital in space? A. Principal quantum number B. Azimuthal quantum number C. Magnetic quantum number D. Spin quantum number (Linked to SLO 1.1) State one reason why quantum states are important in chemistry. (Linked to SLO 1.1) 1.2 Atomic Orbitals 1.2.1 Definition and shapes of orbitals An atomic orbital is a region around the nucleus of an atom where there is a high probability of finding an electron. Orbitals are solutions to the Schrödinger equation and describe both the energy and spatial distribution of electrons. Each orbital has a characteristic shape that reflects how electrons are distributed in space. Fill in the blank: The simplest orbital, which is spherical in shape, is called the __________________ orbital.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Figure 1.2: Shapes of atomic orbitals 1.2.2 Types of orbitals (s, p, d, f) Orbitals are classified into types based on the azimuthal quantum number (l). The s-orbital (l = 0) is spherical, the p-orbital (l = 1) has three orientations (px, py, pz), the d-orbital (l = 2) has five orientations with more complex shapes, and the f-orbital (l = 3) has seven orientations with intricate structures. These orbitals combine to form subshells, which determine the electronic configuration of atoms. Fill in the blank: The orbital type with three orientations (px, py, pz) is the __________________ orbital.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Plate 1.2: Orientations of p-orbitals 1.2.3 Orbital energy ordering The energy of orbitals increases with both the principal quantum number (n) and the azimuthal quantum number (l). The general order of filling orbitals is given by the Aufbau principle, which states that electrons occupy the lowest energy orbitals first. This order is typically 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, and so on. Exceptions occur in transition metals due to stability considerations. Fill in the blank: The principle that states electrons occupy the lowest energy orbitals first is called the __________________ principle.
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