1. Ch. 4 section 1 Notes
Item #53/56 honors

2. Atoms Atom = is the smallest particle of an element
Existence theorized and named by Democritus in 4th century B.C.!
Atomic Theory grew as a series of models developed from experimental evidence, over time the theories and models were revised

3. Dalton’s Atomic Theory
In 1808 Dalton developed the atomic theory:
Atoms cannot be divided (now false)
All atoms of one element are exactly alike (now false)
Atoms cannot be changed into an atom of a different element. Atoms cannot be created nor destroyed, only rearranged.
Atoms of different elements join in specific ratios to form compounds

4. The next 4 slides are for your information…you do not need to write down 

5. Thompson’s Model
In 1897, Thompson discovered the electron, a negatively charged particle within an atom.
Proposed model of atom with negative charges scattered throughout a ball of positive charge – like berries in a muffin.

6. Rutherford’s Model
In 1911, Rutherford used his gold foil experiment to find the nucleus, a tiny region in the center which contained positively charged protons.

7. Bohr’s Model
In 1913, Bohr showed the electrons moved in orbits like planets orbiting around the sun.

8. Cloud Model
In the 1920’s scientists found electrons do NOT orbit around the nucleus like planets, instead they can be anywhere in a designated “cloud” region, called an energy level.

9. Modern Atomic Model
In 1932, Chadwick discovered the neutron, a neutral particle within the nucleus.
Modern model = at the center of the atom is a tiny nucleus containing protons and neutrons. Surrounding the nucleus is a cloudlike region of moving electrons.

10. Scientist/Model QUIZ
Match the atomic structure/model with the scientist: Dalton, Rutherford, Thompson, Bohr, Chadwick, Democritus
Orbiting planet model
Gold foil experiment
Nucleus
Electron
Proton
Neutron
Energy level
“Atom”

11. Parts of the Atom
Nucleus: atom’s central core, made up of protons and neutrons, is positive in charge
Proton (p+): subatomic particle that has positive charge, has some mass
Neutron (n): subatomic particle that has no charge or is neutral, same mass as proton
Electron (e-): subatomic particle that has a negative charge, relatively no mass

12. Comparison Chart
Atoms have no charge overall since protons balance out electrons.
Particle
Symbol
Charge
Mass
Location
Proton p+ +1
~ 1amu
Nucleus
Neutron n
Electron e- -1
~ 0amu
Outside nucleus

13. Atomic Structure
Atomic Number: number of protons in the nucleus of an atom
Atomic # = # of p+
Determines the identity of the element
Periodic table is organized by atomic number
Ex: What is the atomic number of…
He ______ C ______
N ______ O ______

14. Summary: Create a BRACE MAP to illustrate the structure of the ATOM
Use the following words:
electrons atom electron cloud
Neutrons nucleus protons

15. Organizing The Elements 11-2-12 Page #
Meet the Elements Song
Chapter 4 Section 2 Notes
Organizing The Elements
Page #

17. I. Mendeleev’s Periodic Table
By 1869, 63 elements had been discovered. Mendeleev found a way to organize them.
He arranged them by atomic mass, the average mass of all the isotopes of an element.
He noticed a pattern of properties in the table and was able to predict where future elements would occur!

18. II.Modern Periodic Table
The modern periodic table is organized by the number of protons or atomic number.
The properties of an element can be predicted from its location on the periodic table.
According to periodic law, when elements are arranged this way, similarities in their properties will occur in a regular pattern.

19. III. Finding Your Way Around The Periodic Table:
Classes of Elements:
Elements are classified as metals, semimetals, or nonmetals.
The zigzag line on the periodic table separates the metals from the nonmetals

20. III. Finding Your Way Around The Periodic Table:
Periods:
The horizontal rows.
The properties of elements in a row follow a repeating pattern as you move across each period.

21. III. Finding Your Way Around The Periodic Table:
Groups (Families):
The vertical columns (top to bottom).
Elements in the same group have similar characteristics.

22. III. Finding Your Way Around The Periodic Table:
Reading the Data:
Each square in the table gives:
atomic number
chemical symbol
element name
atomic mass
Chemical Symbol = representation of an element usually consisting of 1 or 2 letters

23. Meet The Elements…
Meet the Elements Song

24. State of Matter
Periodic Table displays the state of matter element is in at room temperature
Solids: Most common on table
Liquids: Only 2-5 total on table
Gases: in upper, right hand corner

25. Classification
Metals: elements that are shiny, bendable, conduct heat and electricity well.
Most common, take up left and middle of table
Nonmetals: elements that conduct heat and electricity poorly.
Located in upper, right corner of table
Metalloids: located in between metals and nonmetals, on “staircase”
Semiconductors: element that conducts fairly well

26. Chapter 4 section 3 Notes
Metals
November 6th
Notebook page 81

27. Properties of Metals
The Reactivity of metals tends to decrease as you move from left to right across the periodic table
Physical Properties:
Luster (shiny)
Malleability = material can be hammered or rolled into sheets/shapes
Ductility = material can be pulled out into wire
Thermal conductivity = ability to transfer heat
Electric conductivity = ability to transfer electric current

28. Properties of Metals Chemical Properties:
Reactivity = ease and speed substance reacts with other substances
Decreases as you move from left to right on table!
Corrosion = gradual wearing away of a metal due to chemical reaction

29. Alkali Metals Group 1: Alkali Metals
React w/ other elements by losing 1 electron
Super reactive; always found in compounds, never alone in nature
Soft, shiny
Ex: sodium, lithium, potassium

30. Group 1: Alkali Metals
Turn to page 76 in your notebook and label your periodic table.

31. Alkaline Earth Metals Group 2: Alkaline Earth Metals
Hard, gray-white, good conductor of electricity, fairly reactive
Form compounds found in limestone and in human body
React by losing 2 electrons
Ex: magnesium, calcium, barium

32. Group 2: Alkaline Earth Metals
Turn to page 76 in your notebook and label your periodic table.

33. Transition Metals Groups 3-12, Group that contains the MOST elements
Conduct heat and electricity
Hard, shiny, colorful
Ex: copper, iron, mercury, silver, gold, nickel

34. Metals in Mixed groups
Groups 13-15, some are metals (Aluminum, Gallium, Indium, Thallium, tin, lead, bismuth)
Never found uncombined in nature

35. Metals in Mixed Groups

36. Lanthanides Atomic numbers 57-71,
rare earth metals, used to make alloys

37. Actinides Atomic numbers 89-103
radioactive, some are synthetic (man-made), unstable (Uranium)

38. Synthetic Elements
Synthetic elements are made by scientists by forcing nuclear particles to crash into one another.
The nuclei break apart quickly so this makes it difficult to determine properties of newly discovered elements
Elements numbered 92 and greater
Particle accelerator = moves atomic nuclei at high speeds causing them to crash into each other, sometimes combine into single nuclei

40. November 7, 2012 Notebook Page 83
Chapter 4 Section 4
Nonmetals,
Inert Gases, and
Semimetals
November 7, 2012
Notebook Page 83

41. Nonmetals Physical Properties: Dull Brittle
Poor conductor of heat and electricity
Basically the OPPOSITE of metals!
Chemical Properties:
Gain or share electrons
Metals and nonmetals often react together

42. Nonmetals Located on the right side of table Abundant on Earth
Oxygen and Nitrogen make-up 99% of atmosphere
Carbon is in more compounds than any other elements combined!

43. Group 17: Halogens
Very reactive
Dangerous to humans
Ex: Fluorine, Chlorine, Bromine, Iodine, Astatine
Group 18: Noble/Inert gases:
Unreactive
Do not usually form compounds
Ex: Helium, Neon, Argon, Krypton…

44. Semimetals/Metalloids
Contains only 8 elements,
found along boundary between
metals and nonmetals
Have properties of both metals
and nonmetals
Ex: Boron, Silicon, Arsenic…
Are semiconductors: conduct heat and electricity under certain conditions
Silicon used in computer chips to speed up conduction

45. Radioactive Elements
4-5

46. Radioactivity
Radioactive decay = atomic nuclei of unstable isotopes release fast-moving particles and energy.
Radioactivity = element which spontaneously emits radiation
First discovered by Becquerel in 1896 with uranium.

47. Types of Radioactive Decay
Radioactive decay can produce 3 types of radiation:
Alpha Decay: an alpha particle consists of 2 protons and 2 neutrons and is positively charged.
Can be stopped by a thin layer
Beta Decay: a neutron is converted into a beta particle, a fast-moving electron
Can be stopped by thick material
Gama Decay: high-energy waves
Can only be stopped by thick concrete or lead

49. As uranium decays it becomes multiple elements releasing multiple types of radiation!

50. Uses of Radioactive Isotopes
Radioactive isotopes can include the tracing steps of a chemical reactions, industrial processes, and diagnosing and treating disease.