Ce diaporama a bien été signalé.
Nous utilisons votre profil LinkedIn et vos données d’activité pour vous proposer des publicités personnalisées et pertinentes. Vous pouvez changer vos préférences de publicités à tout moment.
Prochain SlideShare
Chargement dans…5
×

# The Periodic Table

5 913 vues

Publié le

Publié dans : Technologie
• Full Name
Comment goes here.

Are you sure you want to Yes No

Voulez-vous vraiment ?  Oui  Non
Votre message apparaîtra ici

Voulez-vous vraiment ?  Oui  Non
Votre message apparaîtra ici
• This is Fancy!

Voulez-vous vraiment ?  Oui  Non
Votre message apparaîtra ici

### The Periodic Table

1. 1. The Periodic Table
2. 2. What do you think? Agree or Disagree •The elements on the periodic table are arranged in rows in order they were discovered. •The properties of an element are related to the elements location on the periodic table. •Fewer than half of the elements are metals. •Metals are usually good conductors of electricity. •Most of the elements in living things are nonmetals. •Even though they look very diﬀerent, oxygen and sulfur share some similar properties.
3. 3. Mendeleev: Developing a Periodic Table • In 1869 a Russian chemist, inventor and teacher names Dimitri Mendeleev. formulated the Periodic Law. He used it to correct the properties of some already discovered elements and also to predict the properties of elements yet to be discovered.
4. 4. Mendeleev: Developing a Periodic Table •Mendeleev studied the physical properties such as density, colour, melting point and atomic mass of each element. •Mendeleev also studied chemical properties such as how each element reacted with other elements. •He arranged the elements in a list using their atomic masses. •He noticed that the properties of the elements seemed to repeat in a pattern. •When Mendeleev placed his list of elements into a table, he arranged them in rows of increasing atomic mass. Elements with similar properties were grouped in the same columns
5. 5. Periodic Table: Patterns in Properties •Mendeleev noticed that melting point is one property that shows a repeating pattern. •Boiling point and reactivity also follow a periodic pattern.
6. 6. Periodic Table: Predicting Properties •When Mendeleev arranged the elements by increasing atomic mass, there were large gaps between some elements. •He predicted that scientists would discover elements that would ﬁt into these spaces. •He also predicted that the properties of these elements would be similar to the known elements in the same column. •He was right! Both predictions turned out to be true!
7. 7. Periodic Table: Predicting Properties •Mendeleev believed that the atomic masses of certain elements must be invalid because the elements appeared in the wrong place on the periodic table. •He placed elements whose properties resembled each other’s closer together in the table.
8. 8. Periodic Table: Predicting Properties •In the early 1900’s Henry Moseley solved the problem! •When Moseley listed the elements according to atomic number, columns contained elements with similar properties, such as copper, silver, and gold.
9. 9. •Even today, new elements are created in laboratories, named, and added to the present-day periodic table. •These elements are all synthetic and do not occur naturally on Earth. •Scientists can use the periodic table to predict the properties of new elements they create. Periodic Table: New Elements
10. 10. Periodic Table: Organization •The table is organized into columns, rows, and blocks, which are based on certain patterns of properties.
11. 11. Periodic Table: Element Key •The element key shows an element’s chemical symbol, atomic number, and atomic mass. •The key also contains a symbol that shows the state of matter at room temperature.
12. 12. •A group is a column on the periodic table. •Elements in the same group have similar chemical properties and react with other elements in similar ways. •There are patterns in the physical properties of a group such as density, melting point, and boiling point. •The groups are numbered 1-18. Periodic Table: Groups
13. 13. •The rows on the periodic table are called periods. •The atomic number of each element increases by one as you read from left to right across each period. •The physical and chemical properties also change as you move left to right across a period. Periodic Table: Periods
14. 14. •Almost 3/4 of the elements on the periodic table are metals. •Metals are on the left side and in the middle of the periodic table. Metals: Properties metal nonmetalmetalloid
15. 15. •Luster describes the ability of a metal to reﬂect light. •Gold has good luster and that is why people use it for jewelry. •Gold also conducts electricity, but is too expensive to use in normal electrical wires. Cooper is often used. •Ductility is the ability to be pulled into thin wires. •A piece of gold with the mass of a paper clip can be pulled into a wire that is more than 3 km long! Metals: Physical Properties 3 km
16. 16. An ounce of pure gold the size of a matchbox can be ﬂattened into a sheet the size of a tennis court. •Malleability is the ability of a substance to be hammered or rolled into sheets. Metals: Physical Properties
17. 17. •Density, strength, boiling point, and melting point of a metal are greater than those of other elements. •Except for mercury, all metals are solid at room temperature. Metals: Physical Properties
18. 18. •A chemical property is the ability or inability of a substance to change into one or more new substances. •The chemical properties of metals can diﬀer greatly. •However, metals in the same group usually have similar chemical properties. •For example, gold and other elements in group 11 do not easily react with other substances. Metals: Chemical Properties
19. 19. •The elements in group 1 are called alkali metals. •Alkali metals have similar chemical properties. •They react quickly with other elements, such as oxygen. •Because of this, in nature they only occur in compounds. •Alkali metals have similar physical properties. They have a silvery appearance. •They are soft enough to be cut with a knife. •They have the lowest densities of all metals. Metals: Group 1 - Alkali Metals
20. 20. Li, Na, K, Rb, Cs, Fr Metals: Group 1 - Alkali Metals
21. 21. Metals: Group 1 - Alkali Metals
22. 22. Metals: Group 2 - Alkaline Earth Metals •The elements in group 2 are called alkaline earth metals. •Alkaline earth metals also react quickly with other elements, but not as quickly as alkali metals. •Pure alkaline earth metals do not occur naturally. Instead they combine with other elements to form compounds.
23. 23. Be, Mg, Ca, Sr, Ba, Ra Metals: Group 2 - Alkaline Earth Metals
24. 24. Metals: Group 3-12 - Transition Elements •Groups 3-12 are called transition elements. •Transition elements are in a block at the center and two rows at the bottom of the periodic table.
25. 25. Metals: Group 3-12 - Transition Elements •Many colorful materials contain small amounts of transition elements.
26. 26. Metals: Group 3-12 - Transition Elements •All transition elements are metals with higher melting points, greater strength, and higher densities than the alkali metals and the alkaline earth metals. •Transition elements also react less quickly with oxygen. •Some can occur in nature as free elements, meaning that it is pure form, it is not within a compound. •Because of their high densities, strength, and resistance to corrosion, transition elements make good building materials.
27. 27. Metals: Group 3-12 - Transition Elements •Name one everyday use of a transitional element.
28. 28. Metals: Group 3-12 - Transition Elements •Two rows of transition elements—the lanthanide and actinide series—were removed from the main part of the table so that periods 6 and 7 were not longer than the other periods.
29. 29. Metals: Group 3-12 - Transition Elements •Some lanthanide and actinide series elements have valuable properties. •Lanthanide series elements are used to make strong magnets.
30. 30. Metals: Patterns in Properties •Metallic properties include luster, malleability, and electrical conductivity.
31. 31. Metals: Fireworks blue: copper compounds yellow: sodium compounds white-hot: barium-oxygen compounds or aluminum or magnesium burn green: barium compounds orange: calcium compounds red: strontium and lithium compounds gold: iron burned with carbon purple: mix of strontium and copper compounds
32. 32. Metals: Fireworks
33. 33. •More than 96 percent of the mass of the human body comes from four nonmetals–oxygen, carbon, hydrogen, and nitrogen. Nonmetals •Nonmetals are elements that have no metallic properties. •The four elements that make up most of the human body, along with phosphorus and sulfur, are the six elements in proteins, fats, nucleic acids, and other large molecules in your body and in all other living things.
34. 34. •solid at room temperature (except mercury) •have luster •good conductors of electricity and thermal energy •ductile, malleable Nonmetals: Comparison •many are gases at room temperature •those that are solid have a dull surface, therefore no luster •poor conductors of electricity and thermal energy, therefore good insulators Metals Nonmetals
35. 35. •Phosphorus and carbon are dull, brittle solids that do not conduct thermal energy or electricity. Nonmetals: Properties
36. 36. •With the exception of hydrogen, nonmetals are located on the right side of the periodic table. metal nonmetalmetalloid Nonmetals: Properties
37. 37. •Groups 14-16 contain metals, nonmetals, and metalloids. •The chemical properties of the elements in each group are similar. •The physical properties are quite diﬀerent. Nonmetals: Group 14-16
38. 38. •The term halogen refers to an element that can react with a metal and form a salt. •For example chlorine gas reacts with solid sodium and forms sodium chloride (NaCl). Nonmetals: Group 17: The Halogens
39. 39. Nonmetals: Sodium reacting with the halogen chlorine
40. 40. Nonmetals: Group 17: The Halogens •Halogens react so readily that they can only occur naturally in compounds. They do not exist as free elements. •They even form compounds with other nonmetals, such as carbon. •Halogens are less reactive as you move down the group.
41. 41. Nonmetals: Group 18: The Noble Gases •The elements in group 18 are known as the noble gases. •Unlike the halogens, the only way elements in this group react with other elements is under special conditions in a laboratory. •Of all the elements, hydrogen has the smallest atomic mass and is the most common element in the universe.
42. 42. Nonmetals: Group 18: The Noble Gases •These elements were not discovered when Mendeleev constructed his periodic table because they do not form compounds naturally. •Once they were discovered they ﬁt into a group at the far right of the table.
43. 43. Nonmetals: Hydrogen •Hydrogen is most often classiﬁed as a nonmetal because it has many properties like those of nonmetals. •However, hydrogen also has some properties similar to those of the group 1 alkali metals. •Under conditions on Earth, hydrogen usually behaves as a nonmetal.
44. 44. •Between the metals and the nonmetals on the periodic table are the metalloids. Metalloids: Properties
45. 45. •A metalloid is an element that has physical and chemical properties of both metals and nonmetals. •Silicon is the most abundant metalloid in the universe. Metalloids: Properties
46. 46. •Remember that metals are good conductors of electricity and thermal energy. Nonmetals are poor conductors. •A property of metalloids is the ability to act as a semiconductor. •A semiconductor conducts electricity at high temperatures, but not at low temperatures. •At high temperatures metalloids act like metals and conduct electricity. •At lower temperatures metalloids act like nonmetals and stop electricity from ﬂowing. •This property is useful in electronic devices such as computers, tv’s and solar cells. Metalloids: Properties
47. 47. •An element’s position on the periodic table tells you a lot about the element. •Understanding the properties of elements can help you decide which element to use in a given situation. Metalloids: Properties