Science and Technology for UPSC Examinations [Chemistry] Part 9- Notes on Alkali metals

This family is Group 1 of the periodic table and includes lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr).

• Hydrogen is a nominal member because it rarely shows any similar property. So Hydrogen is not among the alkali metals.
• Alkali metals are all highly reactive and are never found in elemental forms in nature.
• They are usually stored immersed in mineral oil or kerosene (paraffin oil) because of their high reactive nature.
• They have low melting points and densities.
• All alkali metals have silver color except caesium which has a golden color.
• the react with halogens and make salts for example NaCl (table salt)
• They react with water and make Hydroxides for example NaOH
• Potassium and rubidium are naturally weakly radioactive elements and they each contain a long half-life radioactive isotope.
• Under standard conditions Lithium is the lightest metal and the least dense solid element.
• Lithium carbonate is used in use in psychiatry
  
• Organolithiums are also used in polymer synthesis and for creating carbon-carbon polymers.
• Lithium batteries are disposable (primary) batteries with lithium metal or lithium compounds as an anode, while the Lithium ion batteries are high energy-density rechargeable batteries.
• Al-Li alloys are used in aeronautics.
• The sodium vapor lamp uses sodium in an excited state to produce light.
• Alkali metal as the Na+ ion is vital to animal life.
• Molten sodium is used as a coolant in some types of nuclear reactors.
• It decreases in blood pressure and decreases in sodium concentration sensed within the kidney result in the production of rennin which in turn helps in secretion of ant diuretic hormones
• Animal cells, potassium ions are vital to cell function. They participate in the Na-K pump and in helping to restore the body’s total amount of fluid.
• Sodium is the chief cation in fluid residing outside cells in the mammalian body
• Low sodium intake may lead to sodium deficiency which is known as hyponatremia.
• About 93% of the world potassium production is consumed by the fertilizer industry
• Potassium chloride is used in execution by lethal injection.
• Potassium vapor is used in several types of magnetometers
• Caesium is one among the five metals which are liquid at room temperature. These are Mercury (melting point −39 °C), Francium (27 °C) caesium (28 °C), Gallium (30 °C) & rubidium (39 °C)
• Caesium has been used in the petroleum Industry exploration as caesium formate.
• The caesium atomic clocks use the resonant vibration frequency of caesium-133 atoms as a reference point. Precise caesium clocks measure frequency with an accuracy of from 2 to 3 parts in 1014, which would correspond to a time measurement accuracy of 2 nanoseconds per day, or one second in 1.4 million years.