The Atom and the Periodic Table

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Honors Chemistry 1st Grading Period Power Objectives: Academic Vocabulary: • Articulate elemental and molecular properties utilizing physical • Dalton’s Atomic Theory • electromagnetic spectrum • atom • quantum structures of the atom and the periodic table. (P.O. #1) • Cathode ray • Plank’s constant • electron • photoelectric effect • Characterize interactions between matter and energy. (P.O. #2) • valence electron • photon • Demonstrate how mathematics describes concepts in • nucleus • atomic emission spectrum • proton • ground state chemistry. (P.O. #3) • neutron • quantumanumber • atomic number • De Broglie equation • Design and conduct chemistry investigations. (P.O. #4) • isotope • Heisenberg uncertainty principle • mass number • quantum mechanical model of the atom • atomic mass unit (amu) • atomic orbital • atomic mass • principal quantum number • electromagnetic radiation • principal energy level • wavelength • energy sublevel • frequency • electron configuration • amplitude • Aufbau principle • Hund’s Rule The Atom Enduring Understandings: Essential Questions: • Without atoms the universe would not exist. • What are the similarities and differences of the atomic models of Democritus, Aristotle, and Dalton? • Our descriptions (models) of the structure and properties of • How was Dalton’s theory used to explain the conservation of mass? matter have changed over time, with the acquisition of new • What is an atom? knowledge by experimentation and analysis. • How can the subatomic particles be distinguished in terms of relative charge and mass? • What is an isotope? • The period table was not developed in one day; it is the • Given the mass number and atomic number, how are the number of electrons, protons, compilation of many years of scientists’ research. and neutrons in an atom calculated? • Elements in the same row and column share similar properties • How do the waves and particle natures of light compare? • How is quantum energy related to an energy change of matter? due to their atomic arrangement. • How do continuous electromagnetic spectra and atomic emission spectra compare and • Trends in the organization of the periodic table help us contrast? understand the unique properties of each element. • How do the Bohr and quantum mechanical models of the atom compare? • How are the Aufbau principle and Hund’s rule used to write electron configurations using orbital diagrams and electron configuration notation? .

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The Quantum Mechanical Model of the Atom
The Quantum Mechanical Model of the Atom Quantum Numbers In order to describe the probable location of electrons, they are assigned four numbers called quantum numbers. The quantum numbers of an electron are kind of like the electron’s “address”. No two electrons can be described by the exact same four quantum numbers. This is called The Pauli Exclusion Principle. • Principle quantum number: The principle quantum number describes which orbit the electron is in and therefore how much energy the electron has. - it is symbolized by the letter n. - positive whole numbers are assigned (not including 0): n=1, n=2, n=3 , etc - the higher the number, the further the orbit from the nucleus - the higher the number, the more energy the electron has (this is sort of like Bohr’s energy levels) - the orbits (energy levels) are also called shells • Angular momentum (azimuthal) quantum number: The azimuthal quantum number describes the sublevels (subshells) that occur in each of the levels (shells) described above. - it is symbolized by the letter l - positive whole number values including 0 are assigned: l = 0, l = 1, l = 2, etc. - each number represents the shape of a subshell: l = 0, represents an s subshell l = 1, represents a p subshell l = 2, represents a d subshell l = 3, represents an f subshell - the higher the number, the more complex the shape of the subshell. The picture below shows the shape of the s and p subshells: (notice the electron clouds) • Magnetic quantum number: All of the subshells described above (except s) have more than one orientation.
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Essential Questions and Objectives
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The Scope of Inorganic Chemistry
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Inorganic Chemistry III
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Transition Metal Electron Configurations
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Chapter 1 What Is Organic Chemistry?
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Short Notes on Periodic Table Modern Periodic Table: Earlier Scientists
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States That Each Electron Occupies the Lowest Energy Orbital Available
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Name of Faculty:Dr.Preeti Gupta Designation: Associate Professor Department: Engineering Chemistry Subject:Engineering Chemistry Unit: VII Topic: Periodic Properties
LNCT GROUP OF COLLEGES Name of Faculty:Dr.Preeti Gupta Designation: Associate professor Department: Engineering Chemistry Subject:Engineering Chemistry Unit: VII Topic: Periodic properties LNCT GROUP OF COLLEGES CLASSIFICATION OF ELEMENTS AND PERIODICITY IN PROPERTIES Need for classification: It is very difficult to study individually the chemistry of all the elements and millions of their compounds, Hence to simplify and systematize the study of chemistry of the elements and their compounds, they are classified into groups and periods. Early attempt to classify the elements: Classification of Lavoiser Elements had been classified into two major groups by Lavoiser 1. Metals 2. Non–metals This classification was based on the differences in their properties. Dobereiner’s law of traids: It was first attempt towards classification. He arranged similar elements in a group of three elements called triad and the atomic mass of the middle elements of the traid is approximately the arithmetic mean of the other two. Newland’s law of octaves: When the lighter elements are arranged in order of their increasing atomic weights, then every eighth element is similar to the first element in its properties, similarly as the eighth node of a musical scale is similar to first one. E.g. Na 8thelement resembles in their properties with Li. Similarly, K the 8th element with Na and so on. Lother Meyer arrangement: LNCT GROUP OF COLLEGES The graphs plotting the atomic volumes against atomic weights are known as Lothar Mayer volume curves. The alkali metals have highest atomic volumes. Alkaline earth metals (Be, Mg Ca, Sr, Ba, etc.) which are relatively a little less electropositive.
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Chapter 5 Section 5 2 Electron Configurations in Atoms.Pdf
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AUFBAU PRINCIPLE Mr
AUFBAU PRINCIPLE Mr. Nderitu . The Aufbau principle (from the German Aufbau meaning "building up, construction": also Aufbau rule or building-up principle ) is 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, they assume their most stable conditions ( electron orbitals ) with respect to the nucleus and those electrons already there. According to the principle, electrons fill orbitals starting at the lowest available (possible) energy levels before filling higher levels (e.g. 1s before 2s). The number of electrons that can occupy each orbital is 1 limited by the Pauli exclusion principle . If multiple orbitals of the same energy are available, Hund's rule states that unoccupied orbitals will be filled before occupied orbitals are reused (by electrons having different spins ). The Aufbau Principle - Electronic Structure and the Aufbau Principle 2 Stable atoms have as many electrons as they do protons in the nucleus. The electrons gather around the nucleus in quantum orbitals following four basic rules called the aufbau principle . • no two electrons in the atom will share the same four quantum numbers n, l, m, and s. • electrons will first occupy orbitals of the lowest energy level. • electrons will fill an orbital with the same spin number until the orbital is filled before it will begin to fill of the opposite spin number. • electrons will fill orbitals by the sum of the quantum numbers n and l. Orbitals with equal values of ( n+l) will fill with the lower n values first.
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