Deck 6

Question 1

Define electronegativity

Answer 1

Electronegativity is a measure of the attraction of a bonded atom for the pair of electrons in a covalent bond.

Question 2

Explain how a small charge difference arises in a H-Cl molecule.

Answer 2

• The Cl atom is more electronegative than the H atom
• The Cl atom has a greater attraction for the bonding pair of electron than the H atom.
• The bonding electrons are closer to the Cl atom than the H atom.

Question 3

Define permanent dipole

Answer 3

A permanent dipole is a small charge difference across a bond that results from a difference in the electronegativities of the bonded atoms.

Question 4

Define polar covalent bond

Answer 4

A polar covalent bond has a permanent dipole.

Question 5

Define polar molecule

Answer 5

A polar molecule has an overall dipole,when you take into account any dipoles across the bonds.

Question 6

What is the overall dipole of a symmetrical molecule with polar bonds?

Answer 6

The molecule has no overall dipole because the bond dipoles act in different directions an cancel each other out. Hence you can have a molecule which is a non-polar molecule with polar bonds.

Question 7

Is CCl4 polar, if so/not explain why.

Answer 7

Has a symmetrical shape the several polar bonds cancel each other out. Hence CCl4 is not polar.

Question 8

Is CO2 polar? Why so/not?

Answer 8

Not polar,because it also has a symmetrical shape and the polar bonds cancel each other out.

Question 9

Is BF3 polar?Why so/not?

Answer 9

• Not polar

- Symmetry cancels dipoles

Question 10

What is the most electronegative atom?

Answer 10

Fluorine

Question 11

How does electronegativity increase across the periodical table?

Answer 11

1) Electronegativity increases towards the top right of the Periodic Table.

Question 12

How can electronegativity of the bonding atoms decide whether atoms have an ionic bond or covalent bond?

Answer 12

1) A bond between two elements with small electronegativity will cause the electronegative atom to have the bonded electrons closer to it forming a polar covalent molecule.
2) A bond between atoms of two different elements with a large difference in electronegativity will cause both electrons to be captured by the electronegative atom forming an ionic bond.

Question 13

Note:

Answer 13

Between extremes of 100% ionic and 100% covalent bonding, we have a whole range of intermediate bonds with both ionic and covalent distributions.