module 2: 6.2 electronegativity and polarity

Question 1

define the term electronegativity

Answer 1

the ability of an atom to attract the bonding electrons in a covalent bond

Question 2

what is the most electronegative element

Answer 2

F, Flourine

Question 3

how does electronegativity change across the periodic table

Answer 3

across the periodic table:
- the nuclear charge increases
- the atomic radius decreases
thus the electronegativity increases
going up the periodic table electronegativity increases

Question 4

what electronegativity difference is required for a bond type to be covalent

Answer 4

0

Question 5

what electronegativity difference is required for a bond type to be polar covalent

Answer 5

0 to 1.8

Question 6

what electronegativity difference is required for a bond type to be ionic

Answer 6

greater than 1.8

Question 7

how is the bond shared in a non-polar bond

Answer 7

the bonded electron pair is shared equally between the bonded atoms.
this is due to the bonded atoms having the same or similar electronegativity.
E.g. H2 or Cl2

Question 8

how is the bond shared in a polar bond

Answer 8

the bonded electron pair is shared unequally between the bonded atoms. A bond will be polar when the bonded atoms are different and have different electronegativity values, resulting in a polar covalent bond.
E.g. HCl
the H–Cl bond is polarised with a small partial positive charge on the hydrogen and a small negative charge on the chlorine atoms. This causes the molecule to be polar.
It is a permanent dipole

Question 9

define the term dipole

Answer 9

a dipole is the separation of opposite charges