• When two atoms in a covalent bond have the?same electronegativity?the covalent bond is?nonpolar

The two chlorine atoms have identical electronegativities so the bonding electrons are shared equally between the two atoms

• When two atoms in a covalent bond have?different electronegativities?the covalent bond is?polar?and the electrons will be drawn towards the?more electronegative?atom
• As a result of this:
  • The negative charge centre and positive charge centre do not?coincide?with each other
  • This means that the?electron distribution?is?asymmetric
  • The?less?electronegative?atom gets a partial charge of?δ+?(delta?positive)
  • The?more?electronegative?atom gets a partial charge of?δ-?(delta?negative)
• The greater the difference in?electronegativity?the more polar the bond becomes

Cl has a greater electronegativity than H causing the electrons to be more attracted towards the Cl atom which becomes delta negative and the H delta positive

Dipole moment

• The?dipole moment?is a measure of how?polar?a bond is
• The?direction?of the dipole moment is shown by the following sign in which the?arrow?points to the?partially negatively charged end?of the dipole:

The sign shows the direction of the dipole moment and the arrow points to the delta negative end of the dipole

Answer:

The correct option is?B.

• • You have to calculate the difference in electronegativity for the bonds and then rank them from smallest to largest:

NO? (3.4 - 3.0 =?0.4)

OF_2?(4.0 - 3.4 =?0.6)

CO? ?(3.4 - 2.6 =?0.8)

CF₄? (4.0 - 2.6 =?1.4)