Atomic+Theory

= //The Atomic Theory// =

** //Vocabulary:// **
2. for a given multiplicity, the term with the largest value has the lowest energy. 3. For a given term, in an atom with outermost subshell half-filled or less, the level with the lowest value lies lowest in energy. If the outermost shell is more than half-filled, the level with highest value is lowest in energy.
 * Dalton-** He verified atoms and is known as the Father of the Atomic Theory.
 * Rutherford-** Discovered the nucleus in the atom.
 * Thomson-** Had the "Plum Pudding Model" and stated that electrons float around the positive inside of the atom.
 * Millikan-** He verified the charge of the electron was negative.
 * Chadwick-** Shown that there are neutrons in the nucleus.
 * Bohr-** Discovered the different energy levels for the electron.
 * Cathode Ray-** A beam of electrons emitted from the cathode of a high-vacuum tube.
 * Law of Conservation of Matter:** a fundamental principle of classical physics that matter cannot be created or destroyed in an isolated system.
 * 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 fixed amount of the other will exhibit a simple multiple relation.
 * Law of Definite Proportions-** Law stating that every pure substance contains the same elements combined in the same proportions by weight.
 * Electron Configuration-** the arrangement of electrons in the orbitals of an electron or molecule.
 * Isotopes-** One of two or more atoms having the same atomic number but different mass numbers.
 * Atomic Number-** the number of protons in an atomic nucleus.
 * Atomic Mass(amu)-** a unit of mass equal to 1/12 the mass of the most abundant of carbon, carbon 12.
 * Mass Number-** the number of protons and neutrons in an atomic nucleus.
 * Quantum Number-** any set of real numbers assigned to a physical system that characterize and specify the particle.
 * Aufbau Principle-** electrons fill the lower energy orbitals before filling the higher orbitals.
 * Pauli Exclusion Principle-** it states that no two electrons can have the same four quantum numbers.
 * Hund's Rule-** 3 rules: 1. for a given electron configuration, the term with maximum multiplicity has the lowest energy.
 * Orbital Diagram-** shows how the orbitals of a subshell are occupied by electrons.
 * Heisenberg Uncertainty-** states by precise inequalities that certain pairs of physical properties, such as position and [|momentum], cannot be simultaneously known to arbitrarily high precision.
 * Quantum Leap-** an abrupt change, sudden increase, or dramatic advance.
 * Energy Level-** fixed amount of energy that a system described by quantum mechanics.
 * Excited State-** elevation in energy level above a baseline energy state.
 * Ground State-** the lowest energy state of an atom or particle.
 * Photon-** A particle representing a quantum of light or other electromagnetic radiation.

// Problems: //
**3. Which element has the atomic number of 79?** Gold; Au **4. What did JJ Thomson use to discover the electron?** The cathode ray tube.
 * 1. What exactly is the atomic theory? ** it is idea that matter is made up of little units called atoms. Democritus came up with this idea with the thought in mind that these were invisible units.
 * 2. What is the atomic mass of carbon? ** 12.01 amu.



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The key points we learned are all the different theorists that led to what we now know is the atom and structure of the atom. also big were the rule's associated with the atomic theory.
 * Our LEQ: Who are the discoverers of the atom and what created the basis for the atomic theory?**