Week 1 - Introduction to Materials and Atomic Structure (ANSWERS) PDF

Week 1: Introduction to Materials and Atomic Structure Fundamentals of Materials  Agenda In this week, we will cover the following topics Session Topics Evaluation (Formative) 1. Introduction to material sciences...

Week 1: Introduction to Materials and Atomic Structure Fundamentals of Materials  Agenda In this week, we will cover the following topics Session Topics Evaluation (Formative) 1. Introduction to material sciences 2. Atomic structure 7. Roots of unity Lesson 3. Electron shells Activities in class (3 Hours) 4. Electron configuration 5. Orbital Diagrams  Learning outcomes On successful completion of this session, you will be able to: Learn what is a material and the different types such as: Metals, polymers, ceramics and composites Understand the atomic structure Study the electron shells Know the electron configuration Understand the orbital diagrams. 1. Introduction to Material sciences  Engineering materials Engineers utilise a variety of materials to perform different tasks. The focus is on how to transform materials into useful devices or structure. Materials science is a field that studies and manipulates the composition and structure of materials to control materials properties through synthesis and processing. The basis of materials science is studying the relationship between the structure of materials, the processing methods to make that material, and the resulting material properties.  Why to study Materials? Many engineers and scientists, whether mechanical, civil, chemical, or electronic, will be exposed to or involved in any material at one time or another and in any application with materials. Examples might include: A transmission gear. The superstructure of a building. An oil refinery component. An integrated circuit chip.  What do we need to know about materials? Classification Characterisation Processing Infrared Metals spectroscopy (IR) Rolling Polymers Scanning Electron Deformation Microscopy (SEM) Ceramics X-ray diffraction Casting Composites (XRD) Extrusion Electrical Mechanical Strength Performance Properties Chemical Hardness Properties Resistance Thermal  Engineering materials Engineers utilise a variety of materials to perform different tasks. Today, we will focus on the most important families of materials and their differences: Metals and alloys Polymers Ceramics Composites During this course, we will discuss each classification in detail. 2. Atomic Structure  Introduction Some of the important properties of solid materials depend on atomic arrangements and the interactions that exist among constituent atoms or molecules. Important concepts such as atomic structure, electron configurations in atoms, the periodic table, and the various types of primary and secondary interatomic bonds that hold together the atoms that compose a solid needs to be learned to be familiar with the material structure.  What is an atom? All the materials are made up of atoms What is an Atom? An atom is the smallest particle of a chemical element that can exist. What are atoms made of? Proton Neutrons Electrons  Atomic structure Protons 1.0073amu Positive charge Location: Inside the nucleus Neutrons 1.0087amu No electric charge Location: Inside the nucleus Electrons Nucleus Approximately 0.00055amu Protons and neutrons Negative charge Most of the mass of an atom is in the nucleus Location: outside the nucleus The nucleus is positively charged 3. Electron shells  Electron shells Electron shells The current Atomic structure was proposed by Niels Bohr. In Bohr’s model, electrons are arranged in shells. These shells are defined by the principal quantum number, given the symbol 'n’. The lowest energy shell has n = 1. Other shells have higher energy and higher n. The higher the n of an electron, the further n= 1 from the nucleus it orbits  Subshells Electron shells For atoms with more than one electron, shells are split into sub-shells that have slightly different energies. The difference in energy between sub- shells is much less than the difference in energy between shells. A shell with a given n will have n sub- shells. n= 1 e.g., the n = 3 electron shell has three n= 2 sub-shells. n= 3  Shells and subshells The n = 1 shell has one sub-shell. It is an s sub-shell. The n = 2 shell has two sub-shells. They are an s sub-shell and a p sub-shell. The n = 3 shell has three sub-shells. It has an s sub-shell, a p sub-shell and a d sub-shell. The n = 4 shell has four sub-shells. It has an s sub-shell, a p sub-shell, a d sub-shell and a f sub-shell Summary 1st shell has one subshell (1s) 2nd shell has two subshells (2s, 2p) 3rd shell has three subshells (3s, 3p, 3d) 4th shell has four subshells (4s, 4p, 4d, 4f) s