IIT JEE , AIEEE Forum - Chemistry , Physical Chemistry

shreyaarya

whats the reason behind octet rule?why can the valence shell have 8 electrons only??

BALGANESH

there are large no of exceptions to octet rule

for eg PCl5 - has expanded octet

BF3 - it has incomplete octet

they combine to complete their incomplete shells

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eragon007

the octet rule is not a rule that was made by usin any calculation it was made by a guy named G.n lewis . it just agreed to the periodic table made by mendeleef because by his observation this sort of octets kept repeating in the elements of the table . yes there are exceptions to this rule i.e the duplet rule used in Helium , & the 18 electron rule which overrides this rule in D & F row elements electrons

brainbank

SF6 TOO...DOESN'T OBEY OCTET RULE.I THINK IT IS BASED ON THE ASSUMPTION THAT SINCE NOBLE GASES BEING THE MOST STABLE HAVE OCTET CONFI.SO SCIENTISTS CONCLUDED THAT FOR A MOLECULE TO FORM STABLE BONDS IT SHOULD OBEY OCTET RULE.

CHEERS.........

kachhara

this rule was given to explain stability. actually, it is a fact that full filled subshells are highly stable. the energy of these is the least. as we know, every system in the system tries to have lowest possible level of energy.

djdylan2000

This is because the valence shell p orbital is completely filled, which gives it more stability(less repulsion). this means 2 'S' electrons and 6 'P' electrons in valence shell= 8 valence electrons.

eistien

hey all those which dont have a d orbital or a f obital ie the 2nd period elements obey octect rule others due to the presence on f d orbitalss have the capability to fill in 18 electrons and thus have expanded octect but to find hybridistaion or structure we have to make the central atom attain octect only by(removing double bonds)and providing the necessary charge for the atoms involved try for urself some compound and check Rate if useful!!!

karansingh

all elements aim to acheive noble gas configuration ( 2 electrons in s subshell and 6 electrons in p subshell = 8 electron in last valence shell ), so they go for octet.

surely, exceptions exist in plenty. u can have them from above

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