The s-Block Elements Test - 2

s block comprises of only two groups alkali metal group and alkaline earth metal groups

Group I ( ns¹)elemens  react vigorously with water to produce an alkaline solution thus colectively known as alkali metals

because their oxide and hydroxide are alkaline in nature and these metal oxide are found in earth's crust 

Alkaline earth metals are called so because of two reasons

1. Alkaline earth metals are obtained on earth in the form of ores
2. Oxides and hydroxides of Alkaline earth metals are basic in nature,

However Beryllium fulfills 1st reason but its oxides and hydroxides are amphoteric so sometimes they say it is not alkaline earth metal. but as it is amphoteric IUPAC has accepted this as alkaline earth metal

calcium and megnesium are 2^nd group element of periodic table which are obtaine on earth in the form ore, their oxides and hydroxide are alkaline in nature so they are alkaline earth metals

Na and K are shiny, soft ,highly reactive metal at standard temprature and pressure and electronic configaration of Na & K  is ns^2,,compounds of Na & K are available most aboundenty in nature so thees two are  alkali metal.

Fr is highly radioactive metal, that decays in to astatine,,radium and radon , it is also highly unstable element found only in trace amount on earth.

Correct sequence is NH₂CONH₂ > NH₄N₃ > NH₃NO₃ > NH₄Cl

The alkali metal ions get extensively hydrated in aqueous solution. Smaller the ion more is the degree of hydration.  

Na and K ions help in transmission of nerve impulses , in regulating the flow of water accross the cell membranes and in the transport of sugar and amino acids in to cells. so monovalent sodium and potassium ions found in large proportions in biological fluids