Lecture 6.1- The Periodic Table

Chemists use the properties of elements to sort them into groups.

Chlorine, bromine, and iodine have very similar chemical properties.

Mendeleev arranged the elements in his periodic table in order of increasing atomic mass.

Mendeleev arranged the elements in his periodic table in order of increasing atomic mass.

Mendeleev’s periodic table was used to predict the properties of undiscovered elements.

An Early Version of Mendeleev’s Periodic Table

In the modern periodic table, elements are arranged in order of increasing atomic number.

The periodic law: When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.

The periodic law: When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.–The properties of the elements within a period change as you move across a period from left to right.

The periodic law: When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.–The properties of the elements within a period change as you move across a period from left to right.

–The pattern of properties within a period repeats as you move from one period to the next.

The stair-step line divides the metals from the nonmetals.

Metals are to the left of the stair-step line

Nonmetals are to the right.

Any square with a side on the stair-step line is a metalloid (semi-metal), EXCEPT ALUMINUM.

Any square with a side on the stair-step line is a metalloid (semi-metal), EXCEPT ALUMINUM.

Across a period, the properties of elements become less metallic and more nonmetallic.

Metalloids (semi-metals)

Metals are good conductors of heat and electric current.

Metals are good conductors of heat and electric current.–80% of elements are metals.

Metals are good conductors of heat and electric current.–80% of elements are metals.–Metals have a high luster, are ductile, and are malleable.

Metals are good conductors of heat and electric current.–80% of elements are metals.–Metals have a high luster, are ductile, and are malleable.

–Metals tend to lose electrons.

Metals are good conductors of heat and electric current.–80% of elements are metals.–Metals have a high luster, are ductile, and are malleable.

–Metals tend to lose electrons.–All metals are solids, except Hg.

Uses of Iron, Copper, and Aluminum6.1

6.1

Uses of Iron, Copper, and Aluminum

6.1

Uses of Iron, Copper, and Aluminum

In general, nonmetals are poor conductors of heat and electric current.

In general, nonmetals are poor conductors of heat and electric current.–Non-metals tend to gain e-

In general, nonmetals are poor conductors of heat and electric current.–Non-metals tend to gain e-

–Most non-metals are gases, but some are solids or liquids.

In general, nonmetals are poor conductors of heat and electric current.–Non-metals tend to gain e-

–Most non-metals are gases, but some are solids or liquids.

–A few nonmetals are solids, like sulfur, carbon, and phosphorus.

–Bromine is a dark-red liquid.

A metalloid has some metallic and non-metallic properties.

•Also called semi-metals The behavior of a metalloid can be

controlled by changing conditions.

If a small amount of boron is mixed with silicon, the mixture is a good conductor of electric current. Silicon can be cut into wafers, and used to make computer chips.

The periodic table displays the symbols and names of the elements, along with information about the structure of their atoms.

Groups are labeled 1-18 or 1A-8A

The Group 1 (1A) elements are called alkali metals.

1A

In their elemental form alkali metals are extremely reactive, so they are not naturally found in elemental form.

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In their elemental form alkali metals are extremely reactive, so they are not naturally found in elemental form.

search youtube for brainiac alkali metal to watch this video at home

The Group 2 (2A) elements are called alkaline earth metals.

2A

The nonmetals of Group 17 (7A) are called halogens.

7A

The noble gases are the elements in Group 18 (8A) of the periodic table.

8A

The blimp contains helium, one of the noble gases.

The Representative ElementsElements in groups 1A through 7A are often referred to as representative elements because they display a wide range of physical and chemical properties.

Representative Elements6.2

6.2Representative Elements

6.2Representative Elements

6.2Representative Elements

Transition metals

Transition metals

Inner transition metals