bond polarity

3.1.3.6

what is electronegativity?

the power of an atom (bonded covalently) to attract the bonding pair of e- towards itself

what happens to electronegativity of the elements from group 1 to 7 as you go across the period and why?

• increases

• as there are more/increasing protons in each atom

• (however) electrons are in the same energy level (include this point for 2 markers)

what happens to electronegativity of the elements from group 1 to 7 as you go up each group and why?

• it increases

• because there are less e- shells so outer e- are closer to the nucleus

what is the most electronegative element?

fluorine

what is a non-polar bond?

when atoms in a molecule have equal electronegativity

• therefore the pair of e- are shared equally

what are some examples of non-polar molecules?

• O2

• N2

• Cl2

what is a polar/dipolar molecule/bond?

when two atoms in a molecule have different electronegativity

• the shared pair of e- are attracted towards the more electronegative atom

what is an example of a polar/dipolar molecule?

HF

which element are the shared pair or e- attracted to in the HF molecule?

F as it has a high electronegative charge/is more electronegative than H

what charges does each atom in the molecule HF gain?

• F gets a slightly neg charge

• H gets a slightly pos charge

are symmetrical molecules polar or non-polar?

non-polar

why can’t symmetrical molecules be polar?

because individual dipoles cancel out