ATPT - Atomic Theory and the Periodic Table (Module Overview)
Atomic Theory and the Periodic Table
Introduction
Did you know that Greek philosophers were curious about matter and what matter was composed of over 2,400 years ago? In this module, students will learn the history of the atom, dating back to the days of Aristotle and other Greek philosophers. We'll concentrate on more recent theories and discoveries during the last 200+ years until we arrive at the present day understanding of what comprises an atom. We will learn about the development of the early periodic table and use the periodic table to determine the number of protons, neutrons, electrons, and detect trends for various atoms and their isotopes. Although the nucleus is the bulk of the atom by mass, it is the electrons that pique the interests of chemists most. The arrangement of electrons in the atom will also be studied.
Having a periodic table handy is always helpful. You may always use a periodic table on assignments, quizzes, and tests in this course. A printable copy of the periodic table can be found by CLICKING HERE and in the resources tab above Links to an external site..
Module Lessons Preview
In this module, we will study the following topics:
History of the Atom: The history behind the development of the modern model of the atom is discussed in this lesson. Students will learn about the scientists and experiments that progressively shaped a more accurate model of the atom.
The Atom & the Periodic Table: This lesson explores the relationship between the Periodic Table and the structure and properties of the atom.
Average Atomic Mass: Average atomic mass is calculated using the abundance of the isotopes of an element. Students will investigate the process of calculating average atomic mass.
Structure of the Atom: In this lesson, students will explore the subatomic particles that make up the atom and patterns that result from the arrangement of these particles.
Periodic Trends: One of the reasons the periodic table is so useful is because its structure allows us to determine how some properties of the elements are related to the position on the periodic table. Few tools in science allow us to judge relative properties of a class of objects like this, which makes the periodic table a very useful tool.
Electrons in Atoms: Though electrons are the smallest of the subatomic particles, they have a profound effect on an element’s properties. Students will examine ways to communicate the location and arrangement of electrons in atoms in this lesson.
Key Terms
Atomic Theory & Structure of Atom Key Terms
Democritus - (born c. 460 — died c. 370 BC) Greek philosopher. Though only a few fragments of his work survive, he was apparently the first to describe invisible "atoms" as the basis of all matter. His atoms — indestructible, indivisible, incompressible, uniform, and differing only in size, shape, and motion — anticipated with surprising accuracy those discovered by 20th-century scientists.
Atom - A unit of matter, the smallest unit of an element having all the characteristics of that element and consisting of a dense, central, positively charged nucleus surrounded by a system of electrons.
Atomos - Greek word meaning indivisible or not able to be cut.
Dalton - (born 1766 - died 1844) English scientist who was one of the first to decide that all matter is made up of small particles, or atoms.
Law of Conservation of Mass - The notion that mass, or matter, can be neither created nor destroyed. According to conservation of mass, reactions and interactions which change the properties of substances leave unchanged their total mass; for instance, when charcoal burns, the mass of all of the products of combustion, such as ashes, soot, and gases, equals the original mass of charcoal and the oxygen with which it reacted.
Law of Definite Proportions - elements composing a compound are always present in the same proportions by mass.
Law of Multiple Proportions - law stating that when two elements can combine to form more than one compound the amounts of one of them that combines with a fixed amount of the other will exhibit a simple multiple relation.
Rutherford - (born 1871 - died 1937) New Zealand physicist who named the nucleus and proton and won the 1908 Nobel prize in chemistry.
Nucleon - A proton or a neutron, especially as part of an atomic nucleus.
Proton - A stable, positively charged subatomic particle having a mass 1,836 times that of the electron.
Neutron - An electrically neutral subatomic particle having a mass 1,839 times that of the electron.
Electron - A stable subatomic particle having a rest mass of 9.1066 × 10-28 grams and a unit negative electric charge of approximately 1.602 × 10-19 coulombs.
The Atom & the Periodic Table Key Terms
Period – horizontal rows on the periodic table.
Group – vertical columns on the periodic table.
Nonmetal - substance that does not exhibit such characteristic properties of metals such as hardness, high melting point, malleability, luster, ductility, or the ability to conduct electricity.
Metal - substance that exhibits the characteristics of hardness, high melting point, malleability, luster, ductility, or the ability to conduct electricity.
Metalloid - an element that exhibits properties of both metals and solid nonmetals.
Atomic Number - the number corresponding to the number of protons in an element that is used to identify specific elements.
Isotope - One of two or more atoms having the same atomic number, but different mass numbers, due to a different number of neutrons in the nucleus.
Average atomic mass – the sum of the masses on an element’s isotopes multiplied by each isotope’s relative abundance.
Mass number - The sum of the number of neutrons and protons in an atomic nucleus.
Periodic table - a table of the chemical elements arranged in order of increasing atomic number so that elements with similar atomic structure and similar chemical properties appear in vertical columns.
Periodic Trends
Electronegativity – a measure of the tendency of an atom to attract electrons.
Ionization Energy – the amount of energy required to remove an electron from a neutral atom.
Atomic Radius – half the distance between the nuclei of two like atoms that are covalently bonded.
Effective Nuclear Charge - The nuclear charge experienced by the outermost electrons of an atom.
Electrons in the Atom Key Terms
Photon - The quantum of electromagnetic energy, regarded as a discrete particle having zero mass, no electric charge, and an indefinitely long lifetime.
Spectroscopy - Study of spectra, especially experimental observation of optical spectra.
Subatomic – any smaller part of an atom such as protons, neutrons, and electrons
Orbital Notation – a way to show the location of the electrons in the atom
Quantum number - A set of real numbers assigned to a physical system that individually characterize the properties and collectively specify the state of a particle or of the system.
Orbital - The wave function of an electron in an atom or molecule, indicating the electron's probable location.
Sublevel - One or more orbitals in the electron shell of an atom.
Hund's Rule - If two or more orbitals of equal energy are available, electrons will occupy them singly before filling them in pairs.
Pauli Exclusion Principle - No two electrons may simultaneously occupy the same quantum state.
Aufbau Principle - Used to determine the electron configuration of an atom, molecule, or ion. The principle postulates a hypothetical process in which an atom is "built up" by progressively adding electrons. As they are added, electrons are added to the lowest energy orbitals first (e.g. 1s before 2s).
PERIODIC TABLE OF ELEMENTS Links to an external site.
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