6.2: electronegativity and polarity

define electronegativity

• the power of an atom to attract the pair of electrons in a covalent bond towards itself

factors that affect electronegativity

• atomic radius

• nuclear charge

• electron shielding

what is the trend of electronegativity going down the group?

• there is a decrease in electronegativity going down the group

• nuclear charge increases

• the number of shells increases

• there is more shielding and atomic radius is greater

• therefore, the increase in nuclear charge is negligible and there is less attraction between nucleus and bonding electrons

what is the trend of electronegativity across the period?

• electronegativity increases across the period

• nuclear charge increases

• similar electron shielding

• the nucleus has an increasingly strong attraction for the bonding pair of electrons which results in a smaller radius

what is the most electronegative element?

• fluorine

define non- polar bond

• the bonded pair of electrons is shared equally between the bonded atoms

• can be because the bonded atoms have the same or similar electronegativity

define polar bond

• when the bonded pair of electrons are shared unequally between the bonded atoms

• can be because the bonded atoms have different electronegativity values

how do you draw a dipole arrow

• points from delta positive to delta negative