1. Chapter 5: The Periodic Table
5.1 Organizing the elements
5.2 The Modern Periodic Table
5.3 Representative groups

2. Organization of the Elements
Section 5.1
Organization of the Elements

3. The Search for Order (Reasons for order)
Brings order to seemingly unrelated facts
Helped chemists predict the existence of elements that weren’t discovered yet
Groups elements according to their chemical and physical properties

4. Mendeleev’s Periodic Table
Strategy for organization: What did he look at?
chemical properties
physical properties
atomic mass
density
color
melting point
valence

5. Mendeleev’s Proposal
Elements arranged in rows based on increasing mass.
Elements with similar properties are in same column.
Chart was a Periodic Table/ DEF. arrangement of elements in columns based on a set of properties that repeat.

6. Mendeleev’s Prediction
Table incomplete– elements not yet discovered
Left spaces in table for undiscovered elements

8. Evidence Supporting Mendeleev’s Table
Close match between Mendeleev’s predictions and the actual properties of new elements showed how useful table was.
Ex. Discovery of: Aluminum, Gallium, Scandium, and Germanium

9. The Modern Periodic Table
Section 5.2
The Modern Periodic Table

10. Repeating patterns
Elements in same column are related because properties repeat in regular intervals

11. The Modern Periodic Table
Listed in order of increasing number of protons
Properties of the elements repeat.
Periodic Law- when the elements are arranged in order of increasing number of protons, the properties tend to repeat in a pattern

12. Columns in the Periodic Table
-vertical classification or groupings
-often referred to as families or groups
-each column is numbered 1-18 or 1A through 8A
-elements within the same family have similar properties

13. Rows in the Periodic Table
-horizontal classification or groupings
-each row is called a period
-elements in a period are not alike in properties, properties change greatly across a given row
-the first element in a period is a very active metal
-the last element in most periods is a noble gas
-only seven periods

14. Element Key
Important information about an element is given in each square of the periodic table:
its atomic number
chemical symbol
element name
atomic mass
6 C Carbon 12.01
For example:
Carbon has an atomic number of 6 (or has 6 protons), an atomic mass of and a symbol of C

15. Atomic Mass Two isotopes of copper Makes the average 63.56 amu

16. Metals Majority of elements Luster – shiny.
Ductile – drawn into thin wires.
Malleable – hammered into sheets.
Conductors of heat and electricity.
Include transition metals – “bridge” between elements on left and right of table

17. Non-Metals Properties are generally opposite of metals
Poor conductors of heat and electricity
Low boiling points
Many are gases at room temperature
Solid, non-metals are brittle (break easily)
Chemical properties vary

18. Metalloids Have properties similar to metals and non-metals
Can conduct heat and electricity like metals but not as good

20. Variation Across a Period: Left to Right
Physical and Chemical properties
Atomic size decreases
Metallic properties decrease
Ability to lose an electron decreases
Ability to gain electrons increases
Ion (charged atom) pattern is seen

21. Representative Groups
Section 5.3
Representative Groups

22. Valence electrons The electrons in the outermost energy level
Responsible for most of the chemical properties
When two atoms interact, the outside electrons are the ones affected
Elements in a group have similar properties because they have same number of valence electrons

23. Ten major families: 1. alkali metals 2. alkaline earth metals 3
Ten major families: 1. alkali metals 2. alkaline earth metals 3. transition elements 4. boron family 5. carbon family 6. nitrogen family 7. oxygen family 8. halogen family 9. noble gases 10. rare earth metals

24. Alkali Metals
- one electron in their outermost shell or one valence electron
- soft, silver-white, shiny metals
- bond readily with other substances
- never found uncombined in nature
- samples must be stored in oil to keep them from combining with water or oxygen
- most reactive metals
- Reactivity increases down a group

26. Alkaline Earth Metals - two valence electrons
- lose 2 electrons when combined with other substances
- never found uncombined in nature
- not quite as reactive as the alkali metals
- often mixed with other metals, such as aluminum, to form alloys of strong yet light in weight metals

27. Alkaline Earth Metals cont…
Magnesium
Used to make steel (lighter metal without sacrificing strength)
Key role in photosynthesis (found in chlorophyll)
Calcium
Found in bones and teeth
Chalk, limestone, coral, pearls, toothpaste, plaster

29. 5 B Boron 10.81 Boron Family -have 3 valance electrons Boron
hard and brittle
never found uncombined in nature
found in borax
used to make heat resistant glass (used in laboratories)
5 B Boron 10.81

30. Boron Family 13 Al Aluminum 26.98 Aluminum
most abundant metal in earth’s crust
found in a mineral called bauxite
extremely important metal for industry, light, strong and slow to corrode
13 Al Aluminum 26.98

31. Carbon Family Have 4 valance electrons
Can either gain 4 electrons or lose 4 electrons
Most compounds in the body contain carbon
Silicon 2nd most abundant element in Earth’s crust
Silicon used to tip saw blades

32. Nitrogen Family Have 5 valence electrons Tend to gain 3 electrons
Nitrogen and Phosphorous used in fertilizers
Phosphorous used in matches

33. Oxygen Family Have 6 valence electrons Tend to gain 2 electrons
Oxygen most abundant element
Sulfur used in fertilizers
Oxygen needed to for digestion

34. Halogen Family -have 7 valence electrons -most active nonmetals
-never found free in nature
-react with the alkali metals quite easily
-when halogens react with metals they form compounds called salts
-Fluorine is the most active halogen

35. Halogens cont… Fluorine compounds used in toothpaste
Chlorine used to kill bacteria
Iodine keeps thyroid gland working properly

37. The Noble Gases (Inert Gases)
-normally non-reactive
-also called inert
-all elements in this family are gases
-outermost electron shell is full
-found in small amounts in the earth’s atmosphere (less than 1%)

39. Other Areas Transition Metals Rare Earth Elements Lanthanide series
Actinide Series