The Periodic Table Proposed by Mendeleev. Dmitri Ivanovich Mendeleev 1834-1907 Born in Siberia, the...

The Periodic Table

Proposed by Mendeleev

Dmitri Ivanovich Mendeleev1834-1907

Born in Siberia, the last of at least 14 children, Dmitri Mendeleev revolutionized our understanding of the properties of atoms and created a table that probably adorns every chemistry classroom in the world.

Arrangements

• Periods – Rows – determines the number of energy levels in an atom– Lanthanide Series (57-71) – rare earth

elements– Actinide Series (89-109) – radioactive

elements

Lanthanide Series – Rare Earth Elements

-Not as rare as once thought

-The lanthanides have many scientific and industrial uses. Their compounds are used as catalysts in the production of petroleum and synthetic products. Lanthanides are used in lamps, lasers, magnets, phosphors, motion picture projectors, and X-ray intensifying screens.

Lanthanum Cerium

Actinide Series - Radioactive

They are all radioactive and some are not found in nature. Some of the elements with higher atomic numbers have only been made in labs.

Arrangements (cont.)

• Groups or Families – arranged according to the number of electrons in the outer energy level– IA or 1 – alkali metals– IIA or 2 – alkali earth metals– VIIB or 17 – halogens– VIII or 18 – noble gases – inert gases

                                                     .

Alkali Metals

-Very reactive-One electron in the outer shell -Shiny

-Light weight

Alkali Metals Properties

• Very reactive– Explode when exposed to water

• Do not occur in nature

• One electron in outer shell

• Softer then most metals

• tarnish rapidly even in dry air

• good conductors of heat and electricity

Sodium

                                                     .

Alkaline Earth Metals

-Two electrons in the outer shell -Fairly reactive (not as reactive as Alkali metals

    So we just

• Have an oxidation number of +2

• Very reactive–Not as reactive as Alkali metals

• Not found in nature

• Two electrons in outer shell

• Soft metal

• Low-density

Properties of Alkali Earth Metals

Magnesium tarnishes slightly in air, and finely divided magnesium readily ignites upon heating in air and burns with a dazzling white flame. Normally magnesium is coated with a layer of oxide, MgO, that protects magnesium from air and water.

Magnesium - Mg

The Halogens

They have seven electrons in their outer shell. They are all just one electron shy of having full shells. Because they are so close to being “happy”, they have the trait of combining with many different elements. You will often find them bonding with metals and elements from Group One of the periodic table.

The Halogens are a generally nasty bunch. Think toxic choking fumes. But in compounds with the similarly strong-willed alkali earths, they can be delicious.

F Fluorine

Halogens

• Non-metallic

• “halogen” meaning “salt-former”

• Have 7 electrons in their outer shell

• Oxidation number of -1

• At room temperature, exist in a solid, liquid, and gas form

Halogen Properties

Inert Gases - Noble Gases

All of the inert gases have full outer shells with eight electrons. Oh wait! That's not totally correct. At the top of the inert gases is little helium (He) with a shell that is full with two electrons. The fact that their outer shells are full means they are quite

happy not reacting with other elements.

• Oxidation number of 0

• Have maximum number of electrons in outer shell

• Stable

• unreactive

Properties of the Noble Gases

Metals vs Nonmetals

Metalloids