Ch. 5 - The Periodic Table

I. History of the Periodic TableMendeleev

Mosely

Periodic Law

A. Dmitri Mendeleev

Dmitri Mendeleev (1869, Russian)

• Organized elements by

increasing atomic mass.

• Predicted the existence of

undiscovered elements.

B. Henry Mosely

Henry Mosely (1913, British)

• Organized elements by

increasing atomic number.

• Fixed problems in Mendeleev’s

arrangement.

Properties of elements repeat in a predictable way when atomic numbers are used to arrange elements into groups.

C. Periodic Law

Key Concept

How is the modern periodic table organized?

In the modern periodic table, elements are arranged by increasing number of protons.

Ch. 5 - The Periodic Table

II. OrganizationMetallic Character

Rows & Columns

Table Sections

Periodic Law

• Properties of elements repeat

periodically when the elements are

arranged by increasing atomic

number.

A. Terms

A. Metallic Character

1

2

3

4 5

6

7

Metals Nonmetals Metalloids

A. Metallic Character

The majority of the elements on the periodic table are classified as metals.

• Metals are elements that are good conductors of electric current and heat.

• Except for mercury, metals are solid at room temperature.

• Most metals are solids. • Many metals are ductile;

that is, they can be bent or drawn in to wires. .

A. Metallic Character

Nonmetals generally have properties opposite to those of metals.

• Nonmetals are elements that are poor conductors of heat and electric current.

• Nonmetals have low boiling points – many nonmetals are gases at room temperature.

• Nonmetals that are solids at room temperature tend to be brittle. If they are hit with a hammer, they shatter or crumble.

A. Metallic Character

Metalloid elements are located on the periodic table between metals and nonmetals.

• Metalloids are elements with properties that fall between those of metals and nonmetals.

• For example, a metalloid’s ability to conduct electric current varies with temperature. Silicon (Si) and Germanium (Ge) are good insulators at low temperatures and good conductors at high temperatures.

B. Rows and Columns

1

2

3

4

5

6

7

Representative Elements Transition Metals

B. Rows and Columns

1

2

3

4 5

6

7

Group (Family) Period

Each column in the periodic table is called a Group or Family.

• The elements in a group have the same number of valence electrons, so members of the same group in the periodic table have similar chemical properties.

• This pattern of repeating properties is the periodic law.

B. Rows and Columns

C. Family/Group Names

Group 1 Alkali Metals All have 1 valance electron All form +1 charged ions Hydrogen is NOT a metal and can also

form -1 charged ion. One of the most reactive groups on

periodic table

Family/Group Names

Group 2 Alkaline Earth Metals All have 2 valance electrons All from +2 charged ion

Family/Group Names

Group 3 to 12 Transition Metals All form positive ions but with

different values (+1 to +6)

Family/Group Names

Group 13 Boron Family All have 3 valance electrons All from +3 charged ions Mixture of metalloids and metals

Family/Group Names

Group 14 Carbon Family All have 4 valance electrons Form +4 or -4 charged ion Mixture of metals, metalloids, and

non metals.

Family/Group Names

Group 15 Nitrogen Family All have 5 valance electrons All form -3 ion Mixture of metals, metalloids, and

non metals.

Family/Group Names

Group 16 Oxygen Family All have 6 valance electrons All form -2 charged ions Mostly nonmetals though 1 metal

and one metaloids

Family/Group Names

Group 17 Halogens All have 7 valance electrons All form -1 charged ion Mostly nonmetals though 1 metalloid One of the most reactive groups on

the periodic table

Family/Group Names

Group 18 Noble Gases All have (except He) have 8 valance

electrons Most don’t react at all

They are “noble” All are nonmetal All are gases at room tempature

A. Terms Group # = # of valence e- (except He)

• Families have similar chemical characteristics . Period # = # of energy levels

1A

2A 3A 4A 5A 6A 7A

8A

A. Terms

Valence Electrons• e- in the outermost energy level• Representative elements the number of valance

electrons equals the ones digit• Group 13 = 3 valance electrons

Each column in the periodic table of elements is a Group.Elements in group 1 have ___ valence electron.Elements in group 2 have ___ valence electrons.Elements in group 13 have ___ valence electrons.Elements in group 14 have ___ valence electrons.Elements in group 15 have ___ valence electrons.Elements in group 16 have ___ valence electrons.Elements in group 17 have ___ valence electrons.Elements in group 18 have ___ valence electrons.

B. Rows and Columns

1

2

3

4

5

6

7

8

Each row in the table of elements is a Period.• Elements in period __ have one energy level.• Elements in period __ have two energy levels.• Elements in period __ have three energy levels.• Elements in period __ have four energy levels.• Elements in period __ have five energy levels.• Elements in period __ have six energy levels.• Elements in period __ have seven energy levels.

Horizontally Into Periods

B. Rows and Columns

1234567

B. Lewis Dot Diagrams

Dots represent the valence e-. Ex.: Sodium Ex.: Chlorine

B. Lewis Dot Diagrams

Start by putting one dot on each side of elements symbol.

Once all 4 side have one dot they can double up

There are four pieces of information for each element.

1. _______________

2. _______________

3. _______________

4. ______________

Review

Which element is a halogen?

Which element has 4 valance electrons?

Which element is a alkaline earth metal with 4 energy levels?

Which element forms a charge of -1 ?

Which element forms a charge of +1 ?