Unit 2 The Atomic Model of Matter

1. Unit 2The Atomic Model of Matter Lundquist -- 2016

2. Properties of Matter Unit 2.1

3. Describing Matter Extensive Intensive Amount does not matter Boiling point Melting point Density () phase • Dependent on amount • Mass • Volume • Weight • color

4. Unit 2.1 Note Quiz Questions 1.

5. Describing Matter Substance • has a definite composition (always the same) • Can be identified by unique properties

6. Describing Matter • A group of elements bound together chemically is a compound • Subscript denotes the numbers of atoms of that element are present in a representative unit of that compound. • Table salt, NaCl; sugar, C12H22O11

7. Classification of Matter Pure Substance Molecules compounds but do not have to be different elements, and can be as few as 1 atom Monoatomic elements – Helium Diatomic elements – Bromine (Br2), Iodine (I2), Nitrogen (N2), Chlorine(Cl2), Hydrogen (H2),Oxygen (O2), Fluorine (F2), Common molecules – Carbon dioxide (CO2), water (H2O) • one element or one compound • identified by its unique chemical or physical properties.

8. Classification of Matter Mixtures • combination of 2 or more pure substances • Heterogeneous • Areas of higher concentration • soil, oil & water • Homogenous • Equal distribution of particles • air, Kool-Aid

9. Note Quiz Questions 2.

10. Do p. 11

11. Describing Matter Physical Properties Chemical Properties Requires the substance react with another compound or energy source Caused the atoms to rearrange • Can be observed without changing the substance

12. Note Quiz Questions 3. 4. 5. 6.

13. Do p. 12

14. Describing Matter Physical Change Chemical Change Rearrangement of ATOMS Start ≠ Finish • Change in location or arrangement of molecules • Start = Finish • INCLUDES changes of state

15. Describing Matter • Chemical changes result in the substance being consumed to produce a new substance • Signs of a chemical change • Formation of a gas • Formation of a solid (precipitate) • Change in temperature • Change in color • Production of light

16. Note Quiz Questions 7. 8.

17. 9. Note Quiz Questions chemical 10.

18. Do p. 13

19. The Periodic Table Unit 2.2

20. Elements and Compounds Elements Compound 2+ elements chemically combined Can be broken down chemically Properties differ from elements that make them • Simplest form of matter • ~114 known (92 naturally occurring)

21. History Democritus (460-370 BCE) Made of small invisible parts Can’t be destroyed Coined the term “atomos”

22. History John Dalton (1766-1844) • English chemist, physicist, & meteorologist • Researched colorblindness (daltonism) • theorized that atoms were a defining substance of matter

23. History Dalton’s Theory Elements are atoms Atoms of an element are the same* Atoms cannot be destroyed Combine in whole number ratios Chemical reactions are just recombination

24. History Joseph James Thomson(1856-1940) • Physicist • Nobel prize winner (so did 7 of his students & his son) • Working with electricity in a “vacuum” found that a ray was produced

26. History Joseph James Thomson(1856-1940) • Determined that atoms have a negative component • EXTREMEMLY large charge/mass ratio • Plum Pudding Model (1904) • Plums = e- • Pudding = (+) energy

27. History Ernest Rutherford (1837 - 1937) British physicist Discovered half-life (won Nobel prize) Proved that alpha radiation is a helium atom

28. History Rutherford & The Gold Foil experiment(1911) • Plum pudding model • At the atomic level there is no solid • To test his ideas about a particles • Rolled Au into a VERY thin sheet • Shot a at it

29. History

30. History Originally a planetary model

31. History Niels Bohr (1885 - 1962) • Danish physicist • Studied with Rutherford • Electrons are held in energy levels (distances from the nucleus) • Based of work by Planck, Einstein, Pauli, & Heisenburg

32. History Energy levels: show number of e- Nucleus: write symbol, #p+ and #n0

33. History Robert Millikan • American Physicist • Found the charge/mass of an e- • Won Nobel Prize

34. History Quantum Theory Duality of matter Quantum Theory

35. History Wolfgang Pauli • Developed Pauli’s exclusion principle • Won the Nobel Prize • Two electrons can not be in the same place at the same time

36. History The Periodic Table Mendeleev Moseley Arranged periodic table by nuclear charge

37. History

38. Unit 2.2 Note Quiz Questions 1.

39. Unit 2.2 Note Quiz Questions 2. 3.

40. Unit 2.2 Note Quiz Questions 4.

41. Review

42. The Periodic Table • Rows = periods • Columns = Families / groups • Arranged in increasing nuclear charge (atomic number)

43. The Periodic Table Element Name Atomic Number Elemental symbol Average Atomic Mass

44. The Periodic Table Element Name English names Some come from antiquity

45. The Periodic Table Atomic Number (Z) The number of p+ Also called the nuclear charge Since each p+ is a +1 More (+) charge means more e- needed to neutralized it IF NEUTRAL, Z =# e-

46. The Periodic Table Elemental Symbol Based off English or Latin Calcium = Ca Tungstun = W (wolfram) Helium = He Lead = Pb (plumbum)

47. The Periodic Table Average Atomic Mass Atoms of an element can differ in mass This is the average mass of all known isotopes (###) = no stable nuclei are known

48. Unit 2.2 Note Quiz Questions 5. 6. 7.

49. Isotopes • Atoms of the same element with different masses • Same number of p+ • Same number of e- • DIFFERENT number of n0 • Isotope names are written as the element-mass • Protium = hydrogen-1 • Deuterium = hydrogen-2

50. Isotopes Notation • Way of denoting different isotopes • Z is understood and not always written • Since EVERY atom of element X would have Z protons