Group 1: Alkali Metals

Group 1: Alkali MetalsThe elements of Group 1, the Alkali metals, are:

symbolelectron configurationlithiumLi[He]2s1sodiumNa[Ne]3s1potassiumK[Ar]4s1rubidiumRb[Kr]5s1cesiumCs[Xe]6s1franciumFr[Rn]7s1The word "alkali" received its name from the Arabic word "al qali," meaning "from ashes". These particular elements were given the name "Alkali" because they react with water to form hydroxide ions, creating a basic solution (pH>7). Solutions that have a pH greater than 7 are called alkaline solutions.Appearance

All the Group 1 elements are silvery-colored metals. They are soft, and can be easily cut with a knife to expose a shiny surface which dulls on oxidation.

lithium

sodium

potassiumcesium

rubidiumcesiumCommon Properties

One loosely bound valence electronLargest atomic radii in their periodsLow ionization energiesLow electronegativityHighly reactiveFound naturally in nature, but not in their pure formsOther propertiesextremely soft and silvery in colormalleable and ductile.low boiling and melting pointsgood reducing agents (easily oxidized)less dense than most elementsLi, Na, and K have the ability to float on water because of their low density.

Alkali metals are luminant, colorful flame is produced by them when burned with oxygen.

potassiumsodiumlithiumrubidiumcesiumTrendsElectronegativity and Ionization energy increase from LEFT TO RIGHT and BOTTOM TO TOPAlkali metals have the lowestelectronegativity and ionization energyFrancium is the least electronegative element.Atomic radius increases from RIGHT TO LEFT and TOP TO BOTTOMFrancium is the largest element

Boiling points and melting points increase going BOTTOM TO TOPLithium has the highest boiling point and Francium has the lowest boiling point in Group 1.

Softness of the element down the group increases due to increasing atomic number because the metallic bond will decrease with increase in atomic size.General Reactions1)With Hydrogen2)With Water3)With Halogens4)With Nitrogen5)With Oxygen1)With Hydrogen: all alkali metals react with hydrogen to form hydrides

2M(l) + H2(g) 2MH(s)

2)With Water: Alkali metals and water react violently to form strong bases and hydrogen gas.

2M(s) + 2H2O MOH(aq) + H2(g)

*Reactivity with water increases as you go down the group.3)With Halogens: Alkali metals and halogens combine to form ionic salts

M(s) + X(g) MX(s)

4)With Nitrogen: only Lithium reacts with Nitrogen at room temperature

6Li(s) + N2(g) 2Li3N(s)

5)With Oxygen:Alkali metals form multiple types ofoxides,peroxidesandsuperoxideswhen combined with oxygen:Oxide ion= O2-compounds generally look like M2Oex. Li2OSodium forms PeroxidesPeroxide Ion= O22-compounds generally look like M2O2ex. Na2O2Potassium, Cesium, and Rubidium form superoxidesSuperoxide ion=O2-compounds generally look like MO2ex. KO2Extraction The alkali metals are so reactive they cannot be displaced by another element, so are isolated by electrolysis of their molten salts.Uses of LithiumLithium is used in heat resistive ceramics and glasses.Alloy of Lithium is used in aircraft building.Lithium Deuteride is used as fusion fuel in thermonuclear weapons.Lithium batteries are packed with lot of energy as compared to other metals. Revolutionized devices like cell phones, computers use lithium batteries.Lithium salts are used as mood stabilizing drug.Lithium-6 is a main source for tritium production.Lithium is used in deoxidizing copper and copper alloys.Lithium compounds are used as pyrotechnic colorants in fireworks that produces red luminance.Lubricating greases are produced from Lithium.

Uses of SodiumSodium is used as luster in metals.Liquid Sodium is used as coolant in Nuclear reactors.Sodium salt of fatty acids are used in soap.NaK, an alloy of sodium and potassium, is an important heat transfer agent.Sodium compounds are used in paper, textile, petroleum and chemical industries.Sodium Iodide is used to treat extensive ringworm.Sodium is used in street lights and sodium vapor lamps as it can give yellow glow with bright luminance.Sodium hydroxide is used as oven cleaner.

Uses of PotassiumPotassium chloride is essential for the growth of plants. It is used in fertilizers.Potash improves water retention, yield, nutrient value, taste, color, texture and disease resistance of food crops.Potassium chlorate and potassium nitrate are used in explosives and fireworks.Potassium nitrate is used as a food preservative.Potassium maintains blood pressure and acidity levels in our body.Potassium chromate is used in the tanning of leather and in the manufacture of inks, gun powder, dyes, safety matches etc.,Potassium is essential for normal cell respiration and electrolyte functionPotassium hydroxide is used to make detergents.Potassium helps to pump fluids inside the heart and the nerves.Uses of RubidiumRubidium 82 is used in myocardial perfusion.Rubidium is used in the manufacture of atomic clocks, electronic tubes, photocells.Rubidium is used as working fluid in vapor turbines.It is used as a component in the engines of space vehicles.Rubidium vapor is used in laser cooling.Rubidium chloride is used to induce cells to take up DNA.It is used in thermoelectric generators.Rubidium Carbonate is used in making optical glasses.Due to hyperfine structure of rubidium's energy levels, it is used in atomic clocks.A compound made up of rubidium, silver and iodine, has certain electrical characteristics and is used in making thin film batteries.

Uses of Cesium

Cesium-134 is used in nuclear power industry.Used in photoelectric cells due to its quick electron emission.Cesium is used as catalyst for hydrogenation of certain organic compounds.It is used in propulsion systems.It removes air traces from vacuum tubes.Cesium is used in photovoltaic cells, television image devices, night-vision equipment.Cesium vapor is used in magnetometer.Cesium-137 is used in brachytherapy to treat cancers. (Brachytherapy is a cancer treatment method using radioactive elements)Cesium chloride solution is used in molecular biology for density gradient ultracentrifugation, primarily for the isolation of viral particles, subcellular organelles and fractions, and nucleic acids from biological samples.Cesium is used as a standard in spectrophotometryIt is used in military aircraft.