Which series is the most reactive series? alkyne alkene alkane methane

Hello.

Alkali metals are the most reactive group in the periodic table, not to be confused with Alkaline earth metals.

Also, Methane is a gas, not a group on the periodic table.

they contain triple bond, one sigma bond and 2 pi bonds. Pi bonds are weak and easily broken making the compound active. 

Chemical reaction is the process of breaking down bonds in reactants and forming new bonds in products. 
In Alkynes breaking down bonds is easier so they are more active.

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C) the increase in atmospheric pressure pushes the walls of the balloon outward thus making it  is the answer.hope i you.

Answer : option a) 84explanation :

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.