Topic 6C

Question 1

what are sigma bonds

Answer 1

covalent bonds occur when atomic orbitals of different atoms overlap and the electrons are shared
sigma bonds occur when two orbitals overlap in a straight line between the atoms
they have the highest electron density and therefore the highest bond enthalpy (strong bonds)
C—H

Question 2

what are pi bonds

Answer 2

when there is a covalent double bond and the sigma bond has already formed
the p orbitals on each atom overlaps sideways, above and below the atoms
—
C C
—

There is lower electron density so the bond enthalpy is lower for a pi bond

Question 3

What is an electrophile

Answer 3

an atom/ group of atoms that is attracted to an electron rich area where it accepts a pair of electrons
E+

Question 4

In a hydrogen halide which is delta positive and why

Answer 4

Halogen more electronegative than hydrogen so the hydrogen is delta positive