Atomic Structure
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Atomic Structure






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    Atomic Structure Atomic Structure Presentation Transcript

    • Atomic Theory Atomic Structure Chapter 2 Atoms
    • Discovering the Elements
      • Elements are the building blocks of all matter
    • Elements Intro
    • Atomic Theory
      • “If I have seen further, it is by standing on the shoulders of giants.” Isaac Newton
      • What does this mean to you?
    • Greek Philosopher’s contribution
    • Greek Philosophers
      • Aristotle
        • 4 Elements of matter
      • Democritus
      • matter is made of atoms (cannot be further divided)
      Earth Fire Air Water
    • Modern Theory
      • Alchemist believed that all matter was made of a limited number of elements.
      • Elements are basic substances that cannot be broken down into simpler forms by ordinary means.
      • 92 exist in nature -
      • 20 synthetic -
      • Atoms were tiny particles that could not be divided
      • Each element had its own kind of atom
      • John Dalton proposed that an atom is a sphere of matter that is the same throughout.
      • Marble Model
      John Dalton
      • Came up with the idea of the electron – negatively charged particle
      • J.J. Thomson discovered that all atoms contain electrons, which are tiny, negatively charged particles. Thomson proposed that an atom is a sphere of positive charge. The electrons are mixed uniformly in the sphere.
      • Clay with embedded
      • spheres
      JJ Thomson
    • Ernest Rutherford
      • He hypothesized that almost all the mass and all the positive charge of an atom is concentrated in an extremely tiny nucleus at the center of the atom.
      • Thought electrons traveled in fixed paths around the nucleus called energy levels.
      Niels Bohr
      • Electrons are in random orbits around the nucleus
      • Electrons move rapidly throughout the atom
      • Energy Levels Still Exist
      Electron Cloud
    • Electrons in Energy Levels 2 e - 8 e - 18 e - 32 e -
    • Atomic Structure
      • Arrangement and number of sub-atomic particles
        • Protons
        • Neutrons
        • Electrons
      • Center or core of an atom
      • Contains 99.9% of the weight of an atom
      • Contains protons and neutrons
      • Occupies 1 / 100,000 of the space of an atom
    • Protons
      • Positively Charged Sub-atomic particles
      • Found in the nucleus
      • All protons are a like
      • Weight of 1 proton =
      • 1 atomic mass unit
      • Neutrally charged (no charge) sub-atomic particle
      • Atomic weight of 1 atomic mass unit
      • Found in nucleus
      • The Number of Protons in the nucleus.
      What makes atoms different?
      • Atomic number is the number of Protons in an atom
      • All atoms of a particular element have the SAME number of protons (All Carbon atoms have 6 protons)
      • In a neutral atom, the atomic number = the number of electrons
      Atomic Number
    • What is a neutral atom?
      • Neutral atoms have no overall charge
      • # of Protons = # of Electrons
    • How Many Electrons?
      • Copper (Cu) has an atomic number of 29.
      • How many electrons does it have?
      • Also called atomic weight or Mass Number
      • Sum weight of protons and neutrons in an atom
      Atomic Mass
    • Periodic Table Atomic Number Element Symbol Mass Number 29 Cu 63.546
    • Calculating Neutrons
      • Mass number = protons + neutrons
      • so…..
      • Neutrons = mass number – protons
      How many neutrons does Copper have? 35 Mass # = 63.546 (rounds to 64) Neutrons = 64-29 =
      • Atoms of the same element with different numbers of neutrons.
      Isotopes Carbon 12 Carbon 13 Carbon 14
      • Negatively charged sub-atomic particle
      • Weight = 0.0006 atomic mass unit
      • Move rapidly
      • Form an electron cloud (area where electrons are likely to be)
      • Charged ATOMS
      • # of protons does not equal # of electrons
      • Positive Ion --- cation
        • More protons than electrons
      • Negative Ion --- anion
        • More electrons than protons
    • Number of elements
      • Oddly enough, the exact number of naturally-occurring elements is uncertain. Uranium (atomic number=92) is the element with the highest atomic number found in significant quantities on earth or elsewhere . The elements astatine (atomic number=85) and francium (atomic number=87), along with all the other known elements (up to atomic number 109) were discovered when first made artificially; if they occur naturally, then they exist only in exceedingly small amounts.
    • Bibliography
      • Discovering the Elements. United Learning (1996). Retrieved October 12, 2006, from unitedstreaming:
      • Physical Science Series: Atomic Structure and the Periodic Table. United Learning (1998). Retrieved October 12, 2006, from unitedstreaming: