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Atomic Theory

Atomic Theory. In the Beginning. Atoms originally named by _____________ Believed the a substance could be divided over and over again only to a point If divided further it would not be that substance anymore His atoms were solid, homogeneous spheres. Law of Conservation of Mass.

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Atomic Theory

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  1. Atomic Theory

  2. In the Beginning • Atoms originally named by _____________ • Believed the a substance could be divided over and over again only to a point • If divided further it would not be that substance anymore • His atoms were solid, homogeneous spheres

  3. Law of Conservation of Mass

  4. Law of Definite Proportions

  5. LAW OF MULTIPLE PROPORTIONS

  6. John Dalton • Proposed atomic theory in 1803 • Parts of Theory • His atom is also a solid, homogeneous sphere

  7. Cathode Rays

  8. J.J. Thomson’s Model

  9. Rutherford’s Gold Foil Experiment

  10. Rutherford’s Model

  11. Niels Bohr’s Model

  12. Comparing the Particles • In the nucleus • Protons • Charge= ________ • Mass = ___________________ • Neutrons • Charge= ______ • Mass= ______________________ • Surrounding the nucleus • Electron • Charge= ______ • Mass= _______________________

  13. Elements • Composed of only one type of _________ • Identity is based on ___________ number • Atomic number (___)- number of protons found in that atom (ID number for elements) • Elements are ordered in periodic table according to this number • Mass Number (___)- mass of atom in atomic unit • Really the mass of the __________________________ • Electrons are so tiny that they don’t count

  14. Calculating pne (Ground State) • # of protons= __________________ • # of electrons= _________________ • # of neutrons= _______________________________

  15. Isotopes • Different forms of the same atom type • Differ by number of ____________ (so therefore differ by mass as well) • Isotope names- element name – mass number Lithium-6 Lithium-7 Lithium-8

  16. Ions • Atoms that lose or gain ___________ form ions • Ions have a charge • Cation- ion with a ____________ charge • Anion- ion with a _____________ charge

  17. Cation • Forms when atoms _________ electrons

  18. Anion • Forms when atoms __________ electrons

  19. Naming Ions • Cations • With one common charge • “Name of the element” ion • For example, Ca+2 is calcium ion • Multivalent • “Name of element” (charge in Roman numerals) ion • For example, Fe+2 is iron (II) ion • Anions • “Name of the element with ending changed to –ide” ion • For example Cl- is chloride ion

  20. Calculating pne (Ions) • # of protons= atomic number • # of electrons = • atomic number – charge for cations • Atomic number + charge for anions • # of neutrons= mass number – atomic number

  21. Atomic Masses on the Periodic Table • Atomic masses on periodic table are an average of all naturally occurring ___________ based on their abundance

  22. Calculating Atomic Mass Need Mass of each isotope Fractional abundance of each isotope (must change to fraction if given as %) For each isotope Multiple the mass and the fractional abundance Add all of the answers together to get the atomic mass

  23. Dmitri Mendeleev Proposed period table (1869) Arranged elements according to ________________ Grouped elements by similar properties Left holes for undiscovered elements and predicted their properties

  24. Germanium Prediction

  25. Structure of Modern Periodic Table Elements are arranged by _____________________ Elements occur in rows (or _________)- 7 periods in all Elements occur in columns (or ___________________) with similar chemical properties- 18 in all ______________ law- elements can be organized into patterns in the table based on chemical and physical properties

  26. Periodic Groups

  27. Other Periodic Groupings

  28. Where do they belong? • The two series actually belong in the table like this, but we put them at the bottom to save space

  29. Metals, Nonmetals, and Metalloids • Metal • Good conductor of electricity • Malleable • Ductile • Shiny • Nonmetal • Poor conductor of heat and electricity • Often gas or dull, brittle solid • Metalloid • Properties in between the other two

  30. Natural States of Elements Most occur as solids Br and Hg can occur as a liquid Other occur as gas

  31. Natural States of Elements (cont) • Many elements can exist in different forms naturally • Carbon • Both graphite and diamond are carbon, the atoms are just arranged differently

  32. Diatomic Elements • Element occurs naturally in pairs • 7 elements • Hydrogen (H2) • Nitrogen (N2) • Oxygen (O2) • Fluorine (F2) • Chlorine (Cl2) • Bromine (Br2) • Iodine (I2)

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