1.3 Bonding

Question 1

What is ionic bonding?

Answer 1

Strong electrostatic forces of attraction between oppositely charged ions held in a lattice

Question 2

How high are ionically bonded substances bp and mp?

Answer 2

High, takes a lot of energy to break the strong electrostatic forces pf attraction between oppositely charged ions

Question 3

Do ionic compounds conduct electricity?

Answer 3

Yes, when in solution as the ions are free to move and carry a charge

Question 4

What is simple molecular covalent bonding?

Answer 4

Strong covalent bonds between atoms, weak van der Waals forces of attraction between molecules

Question 5

Do simple molecular substances have a high or low bp/mp?

Answer 5

Low - weak van der Waals forces of attraction between molecules that don’t take much energy to overcome

Question 6

Describe Macromolecular covalent bonding

Answer 6

Lattice of many atoms held together by strong covalent bonds

Question 7

Do substances with macromolecular covalent bonds have high or low bp/mp?

Answer 7

High - It takes a lot of energy to overcome many strong covalent bonds

Question 8

Describe the structure of diamonds?

Answer 8

1. A 3d tetrahedral structure of C atoms
2. Each C atom bonded to four others

Question 9

Do metallic compounds have high/low bp/mp?

Answer 9

High as strong forces of attraction between positive metal ions and negatively charged sea of delocalised electrons

Question 10

How does the strength of metallic bonds change across the periodic table? Why?

Answer 10

1. Increases - Higher Mp + Bp
2. Higher charge on metal ions
3. More delocalised electrons per ion
4. Stronger forces of attraction between them

Question 11

What is electronegativity?

Answer 11

The ability of an atom to attract the pair of electrons (the electron density) in a covalent bond

Question 12

What are the 3 things that affect electronegativity?

Answer 12

1. Nuclear Charge
2. Atomic Radius
3. Electron Shielding

Question 13

How do you get a nonpolar bond?

Answer 13

Both bonding elements have the same electronegativities

Question 14

What is the strongest type of Inter-Molecular force?

Answer 14

H-Bonds

Question 15

What is the weakest type of Inter-Molecular force?

Answer 15

Van der Waals

Question 16

Describe VDW forces of attraction

Answer 16

1. Temporary dipoles are created by the random movement of electrons.
2. Induces dipole in neighbouring molecule
3. Temporary induced dipole-dipole attraction aka van der waals forces of attraction

Question 17

What is permanant dipole-dipole?

Answer 17

1. Some molecules with polar bonds have permanent dipoles

Question 18

Why is ice less dense than liquid water?

Answer 18

1. In liquid water, H-bonds constantly break and reform as molecules move about
2. In ice, the H-Bonds hold the molecules in fixed positions; this makes them slightly further apart than in water

Question 19

When is a dative/covalent bond formed?

Answer 19

Formed when an electron deficient atom accepts a lone pair of electrons from an atom with a lone pair of electrons

Question 20

What does the shape of a molecule depend upon?

Answer 20

1. The number of electrons in the valence shell of the central atom
2. Numbers of these electrons which are in bonded or lone pairs

Question 21

What does the Electron Pair Repulsion Theory state?

Answer 21

1. That electron pairs will take up positions as far away from each other as possible
2. To minimise the repulsive forces between them