+

S Elements

Groups 1 and 2

+Properties of Group 1A

These are (except for hydrogen) soft, shiny, low-melting, highly reactive metals, which tarnish when exposed to air.

The valence electron is easily lost, forming an ion with a 1+ charge.

larger atomic radii and low ionization energies They tend to donate their electrons in reactions

+Group 1- Alkaline Metals

Hydrogen Lithium Sodium Potassium Rubidium Cesium Francium

+Hydrogen- H

1 proton 1 electron 0 neutron 1s1- electron configuration A colorless, highly flammable gaseous element, the

lightest of all gases and the most abundant element in the universe.

Uses- The most common uses of Hydrogen are in Hydrogen Peroxide, H Bomb, Fuel Cells, Fuel, Hydrogen Generators, Hydrogen Powered Cars.

+Lithium -Li

3 protons 3 electrons 4 neutrons 1s2 2s1 A soft, silvery, highly reactive metallic element

that is used as a heat transfer medium, in thermo-nuclear weapons, and in various alloys, ceramics, and optical forms of glass.

Lithium was discovered by Johann Arfvedson in 1817

+Sodium - Na

11 protons 11 electrons 12 neutrons 1s2 2s2 2p6 3s1 A soft, light, extremely malleable silver-white

metallic element that reacts explosively with water

Sodium, referred to as soda by the English, was isolated in 1807 by Sir Humphrey Davy

+Potassium- K

19 protons 19 electrons 20 neutrons 1s2 2s2 2p6 3s2 3p6 4s1 A soft, silver-white, highly or explosively reactive metallic

element that occurs in nature only in compounds. Potassium was discovered by Sir Humphrey Davy in 1807. Glass, Soap, Substitute for table salt, Medical, Fertilizers,

and Gunpowder

+Rubidium- Rb

37 protons 37 electrons 48 neutrons 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1 A soft silvery-white metallic element of the alkali

group that ignites spontaneously in air and reacts violently with water, used in photocells and in the manufacture of vacuum tubes, and fireworks

Rubidium was discovered by Robert Bunsen and Gustav Kirchhoff in 1861

+Cesium- Cs

55 protons 55 electrons 78 neutrons 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s1 A soft, silvery-white ductile metal and liquid at

room temperature, and used in Atomic Clocks Cesium was discovered by Fustov Kirchoff and

Robert Bunsen in 1860

+Francium- Fr 87 protons 87 electrons 136 neutrons 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 5d10

6p6 7s1 An extremely unstable radioactive element of the

alkali metals soft, malleable, ductile, and are good conductors of

heat and electricity. discovered by Marguerite Derey of the Curie Institute

in Paris in 1939. No known use

+Properties of Alkaline Earth Metals

*The Group 2 elements are all metals with a shiny, silvery-white colour. *harder and denser than sodium and potassium *higher melting points than sodium and potassium *Atomic and ionic radii increase as you move down the Group *Three of these elements give characteristic colors when heated in a flame:

Mg brilliant white Ca brick-red Sr crimson Ba apple green

+Group 2A- Alkaline earth Metals

Beryllium Magnesium Calcium Strontium Barium Radium

+Beryllium- Be 4 protons 4 electrons 5 neutrons 1s2 2s2 high-melting, lightweight, corrosion-resistant,

rigid, steel-gray metallic element used as an aerospace structural material, as a moderator and reflector in nuclear reactors, and in a copper alloy used for springs, electrical contacts, fluorescent tubes, and non-sparking tools.

Beryllium was discovered in France by Nicolas-Louis Vauquelin in beryl and in emeralds in 1798

+Magnesium- Mg 12 protons 12 electrons 12 neutrons 1s2 2s2 A light, silvery-white, moderately hard metallic

element that in ribbon or powder form burns with a brilliant white flame. It is used in structural alloys, pyrotechnics, flash photography, and incendiary bombs.

Magnesium was discovered by Joseph Black, in England, in 1755.

+Calcium- Ca 20 protons 20 electrons 20 neutrons 1s2 2s2 2p6 3s2 3p6 4s2 A silvery, moderately hard metallic element that

constitutes approximately 3.5% of the earth's crust and is a basic component of most animals and plants. The most common uses of Calcium are in Dairy products.

Calcium was discovered by Sir Humphrey Davy in 1808

Fifth most abundant element in the earth's crust

+Strontium- Sr

38 protons 38 electrons 40 neutrons 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 A soft, silvery, easily oxidized metallic element that

ignites spontaneously in air when finely divided. Strontium is used in pyrotechnic compounds and various alloys.

The mineral strontianite was recognised by Adair Crawford in 1790

+Barium- Ba 56 protons 56 electrons 81 neutrons 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 A soft, silvery-white alkaline-earth metal, used to

deoxidize copper and in various alloys. Barium was discovered by in 1774 by Carl Scheele and

extracted by Sir Humphrey Davy in 1808 Sparkplugs, Vacuum tubes, Fireworks, Fluorescent

lamps,Paint, Rat poison 

+Radium- Ra

88 protons 88 electrons 138 neutrons 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2

5d10 6p6 7s2 A rare, brilliant white, luminescent, highly radioactive

metallic element found in very small amounts in uranium ores and used in Luminescent paints

Radium was discovered by Marie Curie and her husband Pierre Curie in 1898