How do you determine whether a bond is a sigma or pi bond?

Question

We're studying these two bonds for the next 7 days, and i am absolutely not getting it at all. I know this is a little vague, but I'm not required to know too much in detail, just the basics. Can someone be kind enough to differentiate between the two a little?

Answer 1

A sigma bond is all single bonds. A pi bond is going to be the double and triple bonds. Hard to word it

ex) O=C=O has 2 sigma bons and 2 pi bond
N(triple bond) N has 2 pi bonds and 1 sigma

H-C-C-H would have 4 sigma bonds. hope taht helps

Answer 2

First off, sigma bonds are single bonds; pi bonds are double, triple or other multiple bonds.

Second, when atoms form sigma bonds, they overlap s-, p- or other orbitals in a straight line, atom to atom. So two spherical s-orbitals of hydrogen overlap a little to squish together. Likewise, one lobe of a dumbbell-shaped p-orbital of oxygen overlaps an s-orbital of H in H2O, also squishing together. One way to look at it is that two persons shake hands by extending a right hand only, keeping the left unused.

When atoms form pi bonds, they line up the orbitals to overlap both lobes vertically, top and bottom. Imagine that for some reason, two persons want to shake hands by giving one another a high-five and a low-five at the same time. Two vertical p-orbitals overlap their upper lobes and the lower lobes at the same time.

Pi bonds usually exist in combination with sigma bonds. For example in ethylene, H2C=CH2, one bond of = is a sigma bond formed by overlapping two p-orbitals end-to-end. The second bond is a pi bond from overlap of two more p-orbitals, top and bottom.

Answer 3

You have pi bond if 2 atoms have 4 common electrons.