Unit Seven: Periodic Table

Background to the Periodic Table:

1. Elements are arranged on the periodic table according to similar properties.2. The modern periodic table is organized by increasing atomic number.

Background to the Periodic Table:

1. Dimitri Mendeleev , a Russian scientist, is credits for creating the first periodic table in 1869. At that time, there were only 60 known element and Mendeleev organized them according to their atomic mass. Mendeleev was able to predict the properties of missing elements which were later discovered. These elements fit perfectly in the missing gaps.

2. Henry Mosely later rearranged the periodic table based on increasing atomic number. This arrangement is still used today.

3. The columns on the periodic table are called groups, the rows are called periods. There are 18 groups (columns) and 7 periods (rows) on the periodic table.

Ted ed: Periodic Table

Period

Group or family

Period

Group or Family

Classification of Elements• Elements on the periodic table can be classified in one of the three

following groups:

•Metals•Nonmetals•Metalloids

a. Metals are located on the left side of the periodic tableb. Non metals are located on the right side of the periodic table.c. The six metalloids fall along the “steps”. They include:

Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te)

Classification of the Periodic Table:

Properties of Metals Metals are good conductors of heat and electricity

Metals are malleable

Metals are ductile

Metals have high tensile strength

Metals have luster

Examples of Metals

Potassium, K reacts with water and must be stored in kerosene

Zinc, Zn, is more stable than potassium

Copper, Cu, is a relatively soft metal, and a very good electrical conductor.

Mercury, Hg, is the only metal that exists as a liquid at room temperature

Properties of Nonmetals

Carbon, the graphite in “pencil lead” is a great example of a nonmetallic element.

Nonmetals are poor conductors of heat and electricity Nonmetals tend to be brittle Many nonmetals are gases at room temperature

Examples of Nonmetals

Sulfur, S, was once known as “brimstone”

Microspheres of phosphorus, P, a reactive nonmetal

Graphite is not the only pure form of carbon, C. Diamond is also carbon; the color comes from impurities caught within the crystal structure

Properties of Metalloids

Metalloids straddle the border between metals and nonmetals on the periodic table.

They have properties of both metals and nonmetals.Metalloids are more brittle than metals, less brittle than most nonmetallic solids Metalloids are semiconductors of electricity Some metalloids possess metallic luster

Silicon, Si – A Metalloid Silicon has metallic luster Silicon is brittle like a nonmetal Silicon is a semiconductor of electricity

Other metalloids include:

Boron, B Germanium, Ge Arsenic, As Antimony, Sb Tellurium, Te

Periodic Table: Metallic arrangement• Layout of the Periodic Table: Metals vs. nonmetals

1IA

18VIIIA

12

IIA13

IIIA14

IVA15VA

16VIA

17VIIA

2

33

IIIB4

IVB5

VB6

VIB7

VIIB8 9

VIIIB10 11

IB12IIB

4

5

6

7

MetalsNonmetals

Reading the Periodic Table: Classification

• Nonmetals, Metals, Metalloids, Noble gases

Groups/Families and Chemical Properties:

The vertical columns on the periodic table are called groups. There are 18 groups on the periodic table.

Elements in a group have the same valence electrons and because of this, they have similar chemical properties.

Down the Periodic Table•Family: Are arranged vertically down the periodic table (columns or group, 1- 18 )

•These elements have the same number electrons in the outer most shells, the valence shell.

1IA

18VIIIA

12

IIA13

IIIA14

IVA15VA

16VIA

17VIIA

2

33

IIIB4

IVB5

VB6

VIB7

VIIB8 9

VIIIB10 11

IB12IIB

4

5

6

7

Alkali Family: 1 e- in the valence shell

Alkali Family: 1 e- in the valence shell

Halogen Family: 7 e- in the valence shell

Halogen Family: 7 e- in the valence shell

Groups/Families and Chemical Properties:

Table of element families & properties:

Group #1 Alkali Metals Reactive, soft metals, 1 valence electron

Group #2 Alkaline Earth Metals Reactive metals, harder than alkali metals, 2 valence electrons

Group #17 Halogens Reactive non-metals7 valence electrons

Group #18 Noble Gas Unreactive non-metals, all are gases8 valence electrons

Infamous Families of the Periodic Table

• Notable families of the Periodic Table and some important members:

1IA

18VIIIA

12

IIA13

IIIA14

IVA15VA

16VIA

17VIIA

2

33

IIIB4

IVB5

VB6

VIB7

VIIB8 9

VIIIB10 11

IB12IIB

4

5

6

7

Alkali

Alkaline (earth)

Transition Metals

Noble GasHalogen

Chalcogens