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64 Cards in this Set
- Front
- Back
Atom
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a tiny unit of matter nature's basic particle
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Democritus
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believed matter was discontinuous
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Democritus
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believed in indivisible, smallest particles possible that he named atoms
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Aristotle
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believed matter was continuous
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False statement from Dalton's Atomic Theory
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Indivisible tiny particles called atoms make up all matter.
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False statement from Dalton's Atomic Theory
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All atoms of the same element are exactly alike in shape & mass.
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True statement from Dalton's Atomic Theory
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The atoms of different elements differ from one another.
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True statement from Dalton's Atomic Theory
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Atoms chemically combine in definite whole number ratios to form chemical compounds.
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True statement from Dalton's Atomic Theory
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Atoms are neither created or destroyed in chemical reactions.
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JJ Thompson
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discovered electron by using a cathode ray tube.
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Robert Millikan
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helped to discover the electron’s mass, along with the value of
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First suggestion made after electron discovery
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there must be something positive
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Second suggestion made after electron discovery
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there must be something more massive in the atom because the electron has such a small mass.
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JJ Thompson
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proposed “Plum Pudding” model.
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Description of the Plum Pudding model
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an atom was a blob of positively charged matter where the electrons were stuck like “raisins” in plum pudding.
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Rutherford
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shot alpha particles at a piece of gold foil.
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Rutherford
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concluded that an atom must have a tiny, but massive, positively charged nucleus surrounded by the electrons.
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Rutherford
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concluded from measurements that the atom is mostly empty space.
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Rutherford
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later discovered the proton (p+) as the particle of positive charge in the nucleus.
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Rutherford
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developed an atomic model to describe it structure, commonly called the solar system model.
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James Chadwick
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discovered the neutron (n0).
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Atomic Number
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the number of protons in an atom
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Isotope
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atoms of the same number of protons (same element) with a different number of neutrons.
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Carbon-12 isotope
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the standard which is assigned exactly 12.00 atomic mass units (u).
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Mass Number
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the number of protons and neutrons in an isotope.
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Atomic Weight
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a weighted average of the isotopes based on their mass compared to Carbon-12 and their relative abundance in nature
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Niels Bohr
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tied together the quantum idea with Rutherford’s model to develop his model of the hydrogen atom.
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Bohr’s Theory
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believed that electrons travel in specific, allowed orbits
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Bohr's Theory
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believed that when in these orbits, the electrons do not give off radiation
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Bohr's Theory & the Quantum Theory
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believed that an electron gains or loses energy only when moving from one orbit to the next
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Changing orbits is referred to as
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quantum leaps
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Ground State
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lowest energy state
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Excited States
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any states above ground
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Louis DeBroglie
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developed the theory that electrons travel as a wave
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Schrödinger
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derived an equation that mathematically proved the Quantum theory.
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Heisenberg Uncertainty Principle
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allowed the quantum theory to be widely accepted
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Orbitals
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a three-dimensional shell, a fuzzy region of space where it is probable that you will find the electron, a probability cloud
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Shapes and sizes of orbitals depend on
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the energy of the electrons contained inside them.
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Principle Quantum Number
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describes main energy level
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Principle Quantum
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designated using the following sybolism n = 1, 2, 3, etc.
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Angular Momentum Quantum Number
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defines energy sublevels within the main energy levels
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Angular Momentum Quantum Number
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indicates the shape of the orbital, identified with a letter
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s, p, d, f
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letters used to describe the shape of the orbitals
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Magnetic Quantum Number
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describes an orbital’s orientation in space
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Spin Quantum Number
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describes an electron’s spin orientation
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Pauli’s Exclusion Principle
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No two electrons in an atom can have the same four quantum numbers
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Electron Configuration
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the arrangement of electrons in orbitals
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Phosphorus - 1s22s22p63s23p3
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example of an electron configuration
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Periods
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Horizontal rows numbered 1-7
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Groups
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Also referred to as families, vertical columns
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Column 1
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alkali metals
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Column 2
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alkaline earth metals
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Columns 3 to 12
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transition metals (elements)
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Column 17
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halogens
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Column 18
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noble gases
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Columns 1, 2, 13 to 18
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representative elements
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Rare Earth Elements
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inner transition elements
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Two Series contained in the Rare Earth Elements
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Lanthanide Series & Actinide Series
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The columns of representative elements are numbered according to
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how many outer shell electrons there are.
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Electron dot notations are used to represent
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these outer shell electrons.
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Valence Electrons
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outer shell electrons used in bonding
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Ion
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an atom that gains or loses electrons
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Metals
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tend to lose electrons to form positive ions, cations
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Nonmetals
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tend to gain electrons to form negative ions, anions
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