1 / 37

Chapter 4 notes

Chapter 4 notes. I. GREEK THEORY A. DEMOCRTUS- The universe is made of indivisible pieces of matter called atoms 1. atom- Greek for unable to divide 2. Not able to explain all observations though and was dismissed II DALTON’S THEORY

robertrjones
Download Presentation

Chapter 4 notes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 4 notes • I. GREEK THEORY • A. DEMOCRTUS- The universe is made of indivisible pieces of matter called atoms • 1. atom- Greek for unable to divide • 2. Not able to explain all observations though and was dismissed • II DALTON’S THEORY • A. Every element is made of tiny unique particles called atoms and cannot be subdivided • B. atoms of the same element are exactly alike • C. atoms of different elements can join to form molecules

  2. III ATOMIC THEORY • A. Nucleus- The center of the atom with a positive charge • 1. Protons- positively charged particle in the nucleus with an atomic mass of 1AMU( ATOMIC MASS UNIT) • 2. Neutrons- The neutral charged particle of the nucleus having the mass of 1 amu • B. Electron cloud- The region around the nucleus with a negative electric charge • 1. contains electrons • 2. Rutherford Gold Foil Experiment

  3. B.Ruherford’s gold foil experiment • 1.Hypothesis- the atom is solid and the particles will bounce off • 2.Observations- most of the particles went straight through, except once in a while one would bounce back • 3.New conclusions- the atom is mostly empty except it has a dense core

  4. IV. MODELS OF THE ATOM • A. BOHR’S MODEL- An explanation of electron movement about the nucleus • 1. Suggested energy levels • a. energy levels- any of the possible energies an electron can have in the atom. Level 1= 2 e: • level 2=8e: level 3= 18e: level 4=32: level 5=50 • 1. electrons gain energy to move to a higher level and give up energy when they drop back into a lower level( ground state) • 1. No longer assumed the electron moved in definite orbitals( Heisenberg uncertainty principle)

  5. B. NEW VIEW OF BOHR’S MODEL • 1. Electrons behaves more like waves • 2. spinning fan image- Cannot locate the location of the fan blade at any time, just know it’s in the blur • a. same applies to an electron,- The best we can do is give the probable location of the electron.

  6. C. ENERGY LEVELS OF ELECTRONS • 1. Orbital- the region where there is a high probability of finding the electron. • a. s orbital- the simplest has a spherical shape • 1. 1 possible orientation in space • 2. surrounds the nucleus • b. P orbital- • 1) Dumbbell shaped • 2) 3 orientations in space ( X.Y,Z) • c. d and f orbitals- much more complex • 1) 5 possible d orbitals • 2) 7 possible f orbitals • 2. Electrons occupy the lowest energy levels in the atom, and within the levels they occupy orbitals with the lowest amount of energy.

  7. s- ORBITAL- SPHERICAL

  8. P- ORBITAL

  9. D- orbital

  10. f- ORBITAL

  11. Sub-level organization • Atomic orbitals • 1sLevel 12s2pLevel 23s3p3dLevel 34s4p4d4fLevel 45s5p5d5f5gLevel 56s6p6d6f6gLevel 67s7p7d7f  Level 7

  12. 2. Electrons occupy the lowest energy levels in the atom, and within the levels they occupy orbitals with the lowest amount of energy. • a. s has lowest then p followed by d and f • 3. Valence electrons- The outer level of electrons • a. The combining ability of the atom depends on the valence

  13. IV TOUR OF THE PERIODIC TABLE • A. Organization of the periodic table • 1. Developed by Dmitri Mendeleev 1869 • a. arranged the elements according to repeating properties • b. He left blank spaces for elements yet to be discovered. • 2. Groups similar elements together • a. makes it easier to predict properties • b. arranged based on the number of protons in the nucleus • c. Periodic Law-properties of elements tend to change in a regular pattern when elements are arranged in order of increasing atomic number or the number of protons in their atom.

  14. B. Using the periodic table • 1. Periods- horizontal rows • a. increasing number of protons • b. each period represents the energy levels of electrons. • 2. Groups( family)- the vertical columns • a. tells the number of valance electrons • 1. valence electrons- determines the chemical properties of the element

  15. C Ionization- The process of adding or removing electrons from an atom, • thus forming a charged atom . • 1. remove an electron the atom will have more protons than electrons, and the atom is positive( metals)- CATIONS • 2. add an electron to the atom. The atom will have more electrons than protons, thus it will be negative( nonmetals) ANIONS

  16. D. HOW ATOMS DIFFER IN STRUCTURE • 1. ATOMIC NUMBER(Z)- This tells the number of protons and electrons in an electrically neutral atom. • 2. Mass number- This is the total number of protons and neutrons in an atom. • a. isotope- An atom with the same atomic number, but different atomic mass • 1. Hydrogen- deuterium, tritium, protonal • b. calculating the number of neutrons- The mass number- atomic number

  17. 3. Atomic mass unit- equal to 1/12 the mass of a carbon-12 atom • 4. Average atomic mass- This is an umber which represents the average of the atomic masses including every isotope.

  18. PERIODIC TABLE OF THE ELEMENTS • V.Broad classification- • 1. metals characteristics- left side of P.T. • a. shiny • b. ductile- pulled into wire • c. malleable- pounded into sheets • d. excellent conductors of heat and electricity • e. Donate electrons- become + ion

  19. 2. Nonmetals characteristics- right side of P.T. • a. dull • b. brittle • c. poor conductors • d. Accept electrons= negative ion

  20. 3. Metalliods- along the zig-zag • a. properties of metals and nonmetals • b. semiconductors

  21. VI SURVEY OF THE PERIODIC TABLE

  22. A.ALKALI METALS (Group 1) • 1 soft high reactive metals. • 2.When mixed with water they form a slippery solution that can remove grease. • 3.Alkali metals are bases, and are highly reactive because they have only one electron in the outermost shell….why? • 4. Alkali metals are good conductors of electricity. Sodium is used in street lamps and fog lights. • 5. Lithium is used as a medication to treat depression.

  23. B.ALKALINE EARTH METALS (Group 2) • 1 are harder, denser, stronger, and have higher melting points that the group 1 metals. • 2.These metals are less reactive than group 1 because they have 2 electrons in the outer shell. • 3. In order for them to have a full outer shell they must loose two electrons. • 4.Magnesium is used in construction because of its strength and lightness. • 5.Calcium is the best know of the alkali earth metals.

  24. C. TRANSITION ELEMENTS (Group 3-12) are all metals. • 1.Transition metals are not as reactive as metals in groups 1 & 2. • 2.They are harder denser and have higher melting points than groups 1 and 2. • 3.Transition elements do not have similar electron configurations as do groups 1 & 2. • 4.There are two more periods of transition elements located at the bottom of the periodic table.

  25. D. Boron family- group 13 • 1. Boron- used in control rods of nuclear reactors, and detergents • a. 3 valence electrons • 2. aluminum- Used as a light weight metal in industry.

  26. E. Carbon family • 1. 4 valence electrons • 2. CARBON • a. Basis of life on this planet • b, Bonds with itself and many other elements • 3. Silicon and germanium- the heart of the computer industry • 4. Tin- Acts as a metal - alloys to make useful metals • 5. Lead- Usually the end product of radioactive decay • a. very dense

  27. F. NITROGEN FAMILY • 1. 5 valence electrons • 2. nitrogen and phosphorus- Used in fertilizers and explosives • 3. Arsenic- a poison used in insecticides. • 4. Bismuth- Used in automatic sprinkler systems because it has a low melting point

  28. G. OXYGEN FAMILY • 1)6 valence electrons- wants 2 to be full, fairly reactive • 2) Oxygen- reactive • a. Used in respiration to release ATP • 3) Sulfur- some in ringed forms • a, Vulcanization of rubber- makes rubber harden • b. Selinium- poisonous, but necessary in small amounts • 1. dairy industry- cows • c. Polonium- radioactive

  29. H. HALOGENS- SALT PRODUCERS • 1. 7 valence electrons... very reactive, only want 1 electron • 2. fluorine- very reactive and poisonous • a. Used to etch glass- HF acid • 3. Chlorine- Very poisonous • a. used in bleaches and detergents- sodium hyperchloride • 4. Bromine- purple liquid at room temperature • 5. iodine- Gray crystals • a. sublimes when heated • b. necessary for the proper functioning of the thyroid gland • 6. astatine- Radioactive

  30. I. NOBLE GASES- VERY BORING • A) 8 electrons in the valence level, so all levels are full. • B) He is lighter than air so used in airships • a. helium comes from the Greek work helios which means sun • 1. discovered by studying the spectrum of sunlight • 2) the rest of them are used in lighted signs or as gases to extend the life of light bulbs

  31. VII. USING MOLES TO COUNT ATOMS • A. ITS LIKE A PACKAGING TERM • 1. dozen=12 • 2. gallon= 128 fluid ounces

  32. B. CHEMIST DEAL WITH A LARGE NUMBER OF SMALL PARTICLES. • 1. Mole-The SI unit which describes the amount of a substance • a. 1 Mole of anything is 6.022x1023 of anything • 1) 6.022x1023 is Avogado’s constant

  33. 2. Molar mass(FWIG)- The mass of 1 mole of any substance, or the mass of 6.02x1023 of anything • a. The average atomic mass is the weight of 1 mole of the substance • 1. 16g of oxygen = 1 mole • 2. 18g of H2 O =1Mole • 3.molar mass of NaCl is? • b. The molecular weight of a compound also equals 1 mole

  34. C Using conversion factors for calculating moles • 1. Must make sure all the units cancel away, and end up with the desired units. • PRACTICE • 1. HOW MANY MOLES OF WATER ARE IN 72 g OF WATER • 72gx 1m/18g=4M • 2. HOW MANY PARTICLES ARE IN 72 g OF WATER • 4Mx 6.02x1023 particles/1mole= 24.08x1023 particles • 3. HOW MANY MOLES ARE IN 174g OF NaCl • 174gx 1m/58g=3M • 4.THE NUMBER OF PARTICLES IN NaCl • 4M x 6.02x1023 particles

  35. 30g of HCl=______atom • 30gx 1m/36g x 6.02x1023atoms/1m • 98g of H2 SO4=_______atoms • 98gx 1m/98g x 6.02x1023 atoms/m • 300 g of Ba3 (PO4)2=______atoms • 300g x 1m/601g x 6.02 x1023 /m • 6M of NaCl=_______________atoms • 6M x 6.02 x1023 atoms/m • .9M of H2 O=___________atoms

  36. More practice • 1) 20g Na=__________M • 2) 45g F=___________M • 3) 126g O=__________M • 4) 30g Na2 O=________M • 5) 3M Ba=___________g • 6) 6M CH4=_________g

More Related