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    Hi, can anyone please explain to me how sigma bond is actually formed? I don't really get why. I thought it is the overlapping of the p orbital directly between the bonding atoms. However I didn't get a mark for it in the exam. Do I need to say that sigma bond is the overlapping of the s orbitals directly next to the bonding atoms to form a single covalent bond? Also, someone mentioned the head on overlapping but I thought sigma bond is when the orbitals are next to the bonding atoms though. Thanks.
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    It is net constructive overlap between orbitals- it can be s orbitals, two Pz orbitals or an s and Pz orbital. It is head on overlap (as opposed to side on overlap possible for p orbitals). Not sure why you wouldn't get a mark but I didn't do OCR so can't comment specifically, sorry!
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    (Original post by Poooky)
    It is net constructive overlap between orbitals- it can be s orbitals, two Pz orbitals or an s and Pz orbital. It is head on overlap (as opposed to side on overlap possible for p orbitals). Not sure why you wouldn't get a mark but I didn't do OCR so can't comment specifically, sorry!
    Thank you.
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    (Original post by coconut64)
    Thank you.
    Did you look at what the mark scheme specifically said? It might have wanted to say overlap of a hybridised orbital (e.g. sp3 for an alkane, sp2 for an alkene…)
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    (Original post by KombatWombat)
    Did you look at what the mark scheme specifically said? It might have wanted to say overlap of a hybridised orbital (e.g. sp3 for an alkane, sp2 for an alkene…)
    Good point, though it seems kind of advanced for A level? But as you say, mark scheme or asking a teacher would be a good idea
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    (Original post by Poooky)
    Good point, though it seems kind of advanced for A level? But as you say, mark scheme or asking a teacher would be a good idea
    Huh, I thought hybridisation was in A level - I did IB so obviously we had a different syllabus but we definitely covered it!
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    (Original post by KombatWombat)
    Huh, I thought hybridisation was in A level - I did IB so obviously we had a different syllabus but we definitely covered it!
    I did it almost 4 yeas ago so maybe it's changed but we did it only very, very briefly. Not enough to ask any meaningful questions on it but your answer does sound right considering they were marked wrong
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    (Original post by Poooky)
    I did it almost 4 yeas ago so maybe it's changed but we did it only very, very briefly. Not enough to ask any meaningful questions on it but your answer does sound right considering they were marked wrong
    I had to state that it forms a single covalent bond and that it is a head on overlap. Thanks anyway.
 
 
 
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