1. Table of Contents Book K Ch. 3 – Sec. 1: Pg. 74-79
Introduction to Atoms
Organizing the Elements
Metals
Nonmetals and Metalloids
Radioactive Elements
Ch. 3 – Sec. 1: Pg
Ch. 3 – Sec. 2: Pg
Ch. 3 – Sec. 3: Pg
Ch. 3 – Sec. 4: Pg
Ch. 4 – Sec. 4: Pg

2. Structure of an Atom - Introduction to Atoms
Atoms are made of even smaller particles called protons, neutrons, and electrons.
Protons and neutrons are located in the nucleus.
Electrons move rapidly around the nucleus.
Charges:
Protons (+)
Neutrons (0)
Electrons (-)

3. Models of Atoms - Introduction to Atoms
For over two centuries, scientists have created models of atoms in an effort to understand why matter behaves as it does. As scientists have learned more, the model of the atom has changed.

4. Atoms and Elements - Introduction to Atoms
Each element consists of atoms that differ from the atoms of all other elements.
An element can be identified by the number of protons in the nucleus of its atoms.
Every atom of an element has the same number of protons.
Because atoms are so small, scientists create models to describe them.
A model may be a diagram, a mental picture, a mathematical statement, or an object that helps explain ideas about the natural world.
Atomic number – number of protons in the nucleus of an atom.
Mass number – the sum of protons and neutrons in the nucleus of an atom.
Atoms with the same number of protons and different number of neutrons are called isotopes.

5. Isotopes - Introduction to Atoms
Atoms of all isotopes of carbon contain six protons, but they differ in the number of neutrons. Carbon-12 is the most common isotope.

6. Click the PHSchool.com button for an activity about atoms.
- Introduction to Atoms
More on Atoms
Click the PHSchool.com button for an activity about atoms.

7. Patterns in the Elements
- Organizing the Elements
Patterns in the Elements
Dimitri Mendeleev, a Russian scientist, discovered a set of patterns that applied to elements.
He noticed that a pattern of properties appeared when he arranged the elements in order of increasing atomic mass.
Atomic mass – the average mass of all the isotopes of that element.
Henry Moseley, a British scientist, discovered atomic number, so now we arrange the periodic table by atomic number.
In the periodic table used today, the properties of elements repeat in each period (row) of the table.

8. Finding Data on Elements
- Organizing the Elements
Finding Data on Elements
Each square of the periodic table includes an element’s
atomic number, chemical symbol, name, and atomic mass.

9. Periodic Table Activity
- Organizing the Elements
Periodic Table Activity
Click the Active Art button to open a browser window and access Active Art about the periodic table.

10. Organization of the Periodic Table
- Organizing the Elements
Organization of the Periodic Table
The 18 columns of the periodic table reflect a repeating pattern of properties that generally occur across a period.

11. Organization of the Periodic Table
- Organizing the Elements
Organization of the Periodic Table
The properties of an element can be predicted from its location in the periodic table.
Periods – horizontal rows.
As you move from left to right, properties of the elements change according to pattern.
Groups (families) – vertical columns.
The groups are numbered, from Group 1 on the left to Group 18 of the right.
The elements in group have similar characteristics.

12. - Metals
Properties of Metals
The physical properties of metals include shininess, malleability, ductility, and conductivity.
A malleable material is one that can be hammered or rolled into flat sheets or other shapes.
A ductile material is one that can be pulled out, or drawn, into long wire.
Conductivity is the ability of an object to transfer heat or electricity to another object.

13. Properties of Metals - Metals
The chemical property, reactivity, is the ease and speed with which an element combines or reacts with other elements or compounds.
The gradual wearing away of a metal element due to a chemical reaction is corrosion.
The reactivity of metals tends to decrease as you move from left to right across the periodic table.

14. Metals in the Periodic Table
The metals in Group 1, from lithium to francium, are called the alkali metals. Alkali metals react with atoms of other elements by losing one electron.

15. Metals in the Periodic Table
Group 2 of the periodic table contains the alkaline earth metals. These elements are not as reactive as the metals in Group 1, but they are more reactive than most other metals.

16. Melting Points in a Group of Elements
- Metals
Melting Points in a Group of Elements
The properties of elements within a single group in the periodic table often vary in a certain pattern. The following graph shows the melting points of Group 1 elements (alkali metals) from lithium to francium.

17. Melting Points in a Group of Elements
- Metals
Melting Points in a Group of Elements
Reading Graphs:
As you look at Group 1 from lithium to francium, describe how the melting points of the alkali metals change.
Melting points decrease from lithium to francium.

18. Melting Points in a Group of Elements
- Metals
Melting Points in a Group of Elements
Predicting:
If element number 119 were synthesized, it would fall below francium in Group 1 of the periodic table. Predict the approximate melting point of new element 119.
New element 119 should have a melting point of approximately 25ºC.

19. Melting Points in a Group of Elements
- Metals
Melting Points in a Group of Elements
Interpreting Data:
Room temperature is usually about 22ºC. Human body temperature is 27ºC. Which of the alkali metals are liquids at room temperature? Which might melt if you could hold them in your hand?
None of the alkali metals are liquids at room temperature. Cesium and francium might melt if you could hold them in your hand.

20. Metals in the Periodic Table
The transition metals are less reactive than the metals in Groups 1 and 2.
Ex. iron, copper, nickel, silver, and gold

21. Metals in the Periodic Table
Only some of the elements in Groups 13 through 15 of the periodic table are metals. These metals are not nearly as reactive as those on the left side of the table.
Ex. aluminum, tin, lead

22. Metals in the Periodic Table
Lanthanides are soft, malleable, shiny metals with high conductivity.
They are mixed with more common metals to produce alloys, which are a mixture of metal with one other element, usually another metal.

23. Metals in the Periodic Table
The elements below the lanthanides are called actinides. Many of these elements are so unstable that they last for only a fraction of a second after they are made.

24. Synthetic Elements - Metals
Elements with atomic numbers higher than 92 are sometimes described as synthetic elements because they are not found naturally on Earth.
Instead, elements that follow uranium are made – or synthesized – when nuclear particles are forced to crash into one another.
To make even heavier elements (with atomic numbers above 95), scientists use powerful machines called particle accelerators which move atomic nuclei faster and faster until they reach very high speeds and then crash into each other.

25. Click the SciLinks button for links on metals.

26. Properties of Nonmetals
- Nonmetals and Metalloids
Properties of Nonmetals
A nonmetal is an element that lacks most of the properties of a metal.
Most nonmetals are poor conductors of electricity and heat and are reactive with other elements.
Solid nonmetals are dull and brittle.
Many of the nonmetals are common elements on Earth.
Ex. nitrogen, oxygen, carbon, iodine, sulfur, bromine

27. Properties of Nonmetals
- Nonmetals and Metalloids
Properties of Nonmetals
When nonmetals react with metals, one or more electrons move from the metal atoms to the nonmetal atoms.

28. Families of Nonmetals - Nonmetals and Metalloids
Each element in the carbon family has atoms that can gain, lose, or share four electrons when reacting with atoms of other elements.

29. Families of Nonmetals - Nonmetals and Metalloids
Group 15, the nitrogen family, contains two nonmetals: nitrogen and phosphorus. These non-metals usually gain or share three electrons when reacting with atoms of other elements.
Nitrogen is an example of an element that occurs in nature in the form of diatomic molecules, as N2.
A diatomic molecule consists of two atoms.

30. Families of Nonmetals - Nonmetals and Metalloids
Group 16, the oxygen family, contains three nonmetals: oxygen, sulfur, and selenium. These elements usually gain or share two electrons when reacting with atoms of other elements.

31. Families of Nonmetals - Nonmetals and Metalloids
The Group 17, the halogens, are the most reactive nonmetals. Atoms of these elements easily form compounds by sharing or gaining one electron when reacting with atoms of other elements.

32. Families of Nonmetals - Nonmetals and Metalloids
The elements in Group 18 are known as the noble gases. They do not ordinarily form compounds because atoms of noble gases do not usually gain, lose, or share electrons.

33. Families of Nonmetals - Nonmetals and Metalloids
Because the chemical properties of hydrogen differ very much from those of the other elements, it really cannot be grouped into a family.

34. The Metalloids - Nonmetals and Metalloids
The metalloids have some characteristics of both metals and nonmetals. The most useful property of the metalloids is their varying ability to conduct electricity.
Semiconductors are substances that can conduct electricity.
They are used to make computer chips, transistors, and lasers.

35. Click the SciLinks button for links on nonmetals.
- Nonmetals and Metalloids
Links on Nonmetals
Click the SciLinks button for links on nonmetals.

36. Patterns of properties
Graphic Organizer
Periodic table
is made up of
organizes
Elements
Rows
Columns
in order of increasing
called
called
Atomic
number
Periods
Families
and shows or
Patterns of properties
Groups

37. Radioactivity
Remember…..the number of protons determines the identity of an atom
Ex: Carbon = 6 Oxygen = 8
Nuclear reaction - reaction involving the particles in the nucleus of an atom
Unlike a chemical reaction which only involves an
atom’s electrons
Isotope - atoms with the same number of protons and different numbers of neutrons
Some are unstable if the nuclei do not hold together well
Radioactive decay - the atomic nuclei of unstable isotopes release fast-moving particles and energy
Ex: Uranium, polonium, radium

38. Radioactivity
Marie Curie, Pierre Curie, and Henri Becquerel studied uranium after noticing spontaneous energy release on a photographic plate.
The reaction was occurring within the uranium nuclei
Radioactivity- spontaneous emission of radiation by an unstable atomic nucleus
M. Curie further discovered two new elements which
gave off radioactive energy as well, Polonium and
Radium.

39. Radioactive decay
Natural radioactive decay can produce alpha particles, beta particles, and gamma rays.
Alpha decay - a nucleus loses an alpha particle, which consists of two protons and two neutrons.

40. Radioactive decay
Beta decay - a neutron inside an unstable nucleus changes into a beta particle and a proton.
Beta particle - fast-moving electron given off by a
nucleus during radioactive decay

41. Radioactive decay
Gamma radiation - has no charge and does not cause a change in either the atomic mass or the atomic number.
Consists of high-energy waves.

42. Radioactive decay
The three types of nuclear radiation were named based on how easily each one could be blocked.
Alpha, beta, and gamma are the first three letters of the Greek alphabet.

43. Radioactive dating
Half-life - the length of time needed for half of the atoms of a sample to decay
Each isotope has its own unique half-life
From the amount of an isotope in a fossil, scientists can calculate how many half-lives have passed since the organism was alive. They are then able to estimate the age of the fossil and the surrounding rock.
Radioactive dating - the process of determining the age of an object using the half-life of one or more radioactive isotopes.

44. Radioactive dating
The half-lives of radioactive isotopes range from a fraction of a second to billions of years.

45. Radioactive dating
Because radioactive isotopes can change into different matter and can give off detectable radiation, they are used in:
Determining the ages of natural materials on Earth
Tracing the steps of chemical reactions and
industrial processes
Diagnosing and treating disease
Providing sources of energy

46. Using Radioactive Isotopes
Tracers – radioactive isotopes that can be followed through the steps of a chemical reaction or industrial process.
Used in studying reactions in living organisms.

47. Radioactive Tracers Activity
Click the Active Art button to open a browser window and access Active Art about radioactive tracers.

48. Using Radioactive Isotopes
Medicine:
Can make images of the bone, blood vessel or organ affected
Used to destroy unhealthy cells (iodine-131 for thyroid tumors)
Nuclear Power:
Fuel- can provide electric energy

49. Dangers of Radiation Radiation can: Penetrate living tissue and
interfere with chemical reactions
in living cells
Cause illness, disease, and even death from overexposure
Protection includes:
Wearing protective clothing and
insulating shields
Properly disposing of wastes

50. Click the Video button to watch a movie about radiation.