Modern Periodic Table

Mrs. Coyle

Part I

Introduction. Periods and groups. Metals, nonmetals and metalloids.

The Modern Periodic Table

The Periodic Table is a listing of all the known elements.

The elements are organized by: Atomic number Chemical Properties

Groups and Periods

Group( or Family): a vertical column. Elements in groups have similar chemical properties.

Period: a horizontal row.

Groups and Periods are numbered.

There are 7 periods.

There are 18 numbered columns.

IUPAC

International Union of Pure and Applied Chemistry

1985 new system for labeling groups.

Metals, Nonmetals and Metalloids

Elements can be classified into:

Metals

Nonmetals

Metalloids (semimetals)

MetalsMetalloids

Nonmetals

Actinides and Lanthanides

Physical Properties of Metals

Good conductors of electricity and heat.

Malleable (can be hammered into sheets).

Ductile (can be drawn into wires). Lustrous.

Chemical Properties of Metals

Easily lose electrons.

Form positive (+) ions.

Nonmetal Physical Properties

They do not have the properties of metals.

Nonmetal Chemical Properties

Gain electrons.

Form negative ions.

Part II

Valence Electrons Group 1 Group 2

-Niels Bohr’s Model – Distinct Energy Levels

Periods

The periods (rows) of the periodic table indicate the highest energy level occupied by one or more electrons.

Valence Electrons

The electrons the occupy the highest energy level of an atom.

Valence electrons play a key role in the chemical properties of an element.

“A” Groups (Old System)

The “A” groups are numbered 18.

The number of the “A” groups correspond to the number of valence electrons.

Group 1- Alkali Metals

1 valence electron (ns1)

Form a 1+ ion.

Note: Hydrogen, a nonmetal, is located in the first column because it has one valence electron.

Group 1- Alkali Metals

Lithium

Sodium

Potassium

Rubidium

Cesium

Francium

Sodium’s Reaction with H2O Produces Hydrogen

Reactivity of Alkali Metals

Increases from top to bottom of the group.

Which is more reactive Cesium or Sodium?

Note:

Sodium and Potassium are stored in oil to keep them from reacting with oxygen and water in the air.

Cesium is stored in glass tubes of argon gas( an inert gas).

Group 2- Alkali Earth Metals

Beryllium

Magnesium

Calcium

Strontium

Barium

Radium

Group 2- Alkali Earth Metals

Have 2 valence electrons.

Form 2+ ions.

Group 2- Alkali Earth MetalsReactions with Water

Be does not react with water. Mg reacts with hot water. Ca, Sr, Ba react easily with cold

water.

Which way along the group does reactivity increase?

Notes:

There is Mg in chrolophyll

C55H72O5N4Mg

Calcium is in your bones, chalk, limestone, toothpaste, pearl (all as calcium carbonate).

The Periodic Table