Unit 2: Periodic Table Periodic Law and Labeling

The Periodic Law

When the elements are arranged by increasing atomic number,

The Periodic Law

When the elements are arranged by increasing atomic number,

there is a periodic repetition of their chemical and physical properties.

Dmitri Mendeleev (1834-1907)

• First to notice the element's periodic repetition of properties.

• Designed the first periodic table (in1869)

Mendeleev

Mendeleev

• His periodic table was arranged by atomic mass. (our current PT is arranged by atomic number)

• He was able to predict properties of undiscovered elements.

Labeling the PT• Rows across the

PT are called periods (1-7)

• Columns down the PT are called groups or families (1-18)

Period

Column/ Family

Period

Group/Family

1

765432

67

1142 1516 17

18

43

13

8765 1211109

Groups/Families have 3 naming methods

• #1-18 • 1A-8A • Special family names

1A2A 3A 4A 5A 6A 7A

8A

Family Number Family Name Family Number Family Name

1 Alkali Metals 15 Nitrogen Family

2 Alkaline Earth Metals 16 Oxygen Family

3-12 Main Group Transition Metals 17 Halogens

13 Boron Family 18 Noble Gases

14 Carbon Family

Zigzag on the PT• Metalloids on the PT divide the metals

from the nonmetals.

• They form a zigzag (or staircase) on the PT. Memorize these 8 metalloids!

• Metals are on the left of the metalloids.

• Nonmetals are on the right (don’t forget hydrogen though!)

The Eight Metalloids: Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium,

Polonium, & Astatine

What about the bottom section?

• Elements with atomic numbers 58-71 are called the Lanthanide Series. They are in period 6.

• Elements with atomic numbers 90-103 are called the Actinide Series. They are in period 7.

• These elements fit inside the main group transition metals so they are collectively called the Inner Transition Metals.

Long Periodic TableThis is what the PT would look like if the the inner

transition metals were placed inside the main group.

Inner Transition Metals

The Super Seven!• Diatomic elements are

found in nature as pairs of atoms; two identical atoms bonded together.

• The super seven (diatomic elements) are H2, N2, O2, F2, Cl2, Br2, & I2

Phases!

• 2 liquids

• 11 gases (don’t forget hydrogen!)

• the remaining are solids