ALKALI METALS

Physical Properties

- Alkali metals have low melting points.

- They are malleable, ductile, good conductors of heat and electricity, and are very soft.

- For __metals__, they also have very low densities.

Chemical Properties

- Alkali metals have only one electron in their outer (valence) shell. Therefore, they're ready to lose that one electron in ionic bonding with other elements and are highly reactive

- The alkali metals are the most reactive group of metals in the Periodic Table (some experiments are very dangerous e.g. mixing Lithium and Cesium.)

- Alkali metals react with non-metals

- Alkali metals can explode if they are exposed to water so they are stored in oil to esape from oxygen and water.

Interesting Facts

- Compounds formed by Group 1 metals are usually white solids (that dissolve in water to form colourless solutions)

- Alkali metals are never found in elemental form in nature

The alkali metals get more reactive as you go down the group.

Uses

Lithium:

• used to make:

- medicine (treat mental illness)

- glass (tubes inside TV’s and lenses which darken sunlight)

- air conditioning (used in submarines to remove carbon dioxide)

- dyes (helps dye nylon and paper)

- added to ceramics (noise cones of rockets)

• used to strengthen other metals like magnesium, in alloys

• used in batteries

• suitable for calculators, watches, and cameras

Sodium:

• used to make:

- sewage treatment (neutralizes acid)

- washing powders and liquids (softens water)

- dyeing textiles

- tanning leather

- glass

Potassium:

- essential for the healthy growth of plants

- nitrate is used as a fertilizer

- making explosives and fireworks

Basic Info

LITHIUM

Symbol: Li

Atomic Number: 3

Atomic Mass: 6.941 amu

Melting Point: 180.54 °C (356.972 °F)

Boiling Point: 1347.0 °C (2456.6 °F)

Number of Protons/Electrons: 3

Number of Neutrons: 4

Density @ 20 °C: 0.53 g/cm3

Color: Silvery

Date of Discovery: 1817

Discoverer: Johann Arfvedson

Name Origin: From the Greek word lithos (stone)

Uses: Batteries, ceramics, lubricants

Obtained From: Passing electric charge through melted lithium chloride, spodumene

Isotopes: Li-6, Li-7

SODIUM

Symbol: Na

Atomic Number: 11

Atomic Mass: 22.98977 amu

Melting Point: 97.8 °C (208.04001 °F)

Boiling Point: 552.9 °C (1027.2201 °F)

Number of Protons/Electrons: 11

Number of Neutrons: 12

Density @ 20 °C: 0.971 g/cm3

Color: Silvery

Date of Discovery: 1807

Discoverer: Sir Humphrey Davy

Name Origin: Soda (Na2CO3)

Symbol Origin: From the Latin word natrium (sodium)

Uses: Medicine, agriculture

Obtained From: Table salts and other foods

Isotopes: Na-22, Na-23, Na-24

POTASSIUM

Symbol: K

Atomic Number: 19

Atomic Mass: 39.0983 amu

Melting Point: 63.65 °C (146.57 °F)

Boiling Point: 774.0 °C (1425.2 °F)

Number of Protons/Electrons: 19

Number of Neutrons: 20

Density @ 20 °C: 0.862 g/cm3

Color: Silvery

Date of Discovery: 1807

Discoverer: Sir Humphrey Davy

Name Origin: Potash

Symbol Origin: From the Latin word kalium

Uses: Glass, soap

Obtained From: Minerals (carnallite)

Isotopes: K-39, K-40, K-41, K-42, K-43

RUBIDIUM

Symbol: Rb

Atomic Number: 37

Atomic Mass: 85.4678 amu

Melting Point: 38.89 °C (102.002 °F)

Boiling Point: 688.0 °C (1270.4 °F)

Number of Protons/Electrons: 37

Number of Neutrons: 48

Density @ 20 °C: 1.532 g/cm3

Color: Silver

Date of Discovery: 1861

Discoverer: R. Bunsen

Name Origin: From the Latin word rubidus (red)

Uses: Catalyst, photocells

Obtained From: Lithium production

Isotopes: Rb-81, Rb-82, Rb-83, Rb-84, Rb-85, Rb-86, Rb-87, Rb-88, Rb-89, Rb-90, Rb-90m

CESIUM

Symbol: Cs

Atomic Number: 55

Atomic Mass: 132.90546 amu

Melting Point: 28.5 °C (83.3 °F)

Boiling Point: 678.4 °C (1253.12 °F)

Number of Protons/Electrons: 55

Number of Neutrons: 78

Density @ 20 °C: 1.873 g/cm3

Color: Silver

Date of Discovery: 1860

Discoverer: Fustov Kirchoff

Name Origin: From the Latin word caesius (sky blue)

Uses: Removes air traces in vacuum tubes

Obtained From: Pollucite, lepidolite

Isotopes: Cs-126, Cs-129, Cs-131, Cs-132, Cs-133, Cs-134, Cs-134m, Cs-135, Cs-136, Cs-137, Cs-138, Cs-139

*NOTE: also spelt as Caesium (British)

FRANCIUM

Symbol: Fr

Atomic Number: 87

Atomic Mass: (223.0) amu

Melting Point: 27.0 °C (80.6 °F)

Boiling Point: 677.0 °C (1250.6 °F)

Number of Protons/Electrons: 87

Number of Neutrons: 136

Density @ 20 °C: Unknown

Color: Unknown

Date of Discovery: 1939

Discoverer: Marguerite Derey

Name Origin: After France

Uses: No uses known

Obtained From: Decay of actinium

Isotopes: Fr-212, Fr-221, Fr-222, Fr-223

Links

Alkali Metals by Theodore Gray

Chemical Elements.com - Alkali Metals

Visual Elements: Group 1 - The Alkali Metals