CH3 Bonding

Question 1

What is ionic bonding

Answer 1

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

Question 2

Example of ionically bonded substance

Answer 2

NaCl - Sodium chloride

Question 3

How high are ionically bonded substances BP and MP - why

Answer 3

High - Takes lots of energy to break strong electrostatic forces of attraction between oppositely charged ions

Question 4

Do ionic compounds conduct electricity - why

Answer 4

Yes - when molten or in solution as the ions are free to move and carry charge

Question 5

What is simple molecular covalent bonding

Answer 5

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

Question 6

Are there any lone electrons in simple covalent bonding

Answer 6

No - they are all involved in bonding

Question 7

Can simple molecular molecules conduct electricity - why

Answer 7

No - all electrons used in bonding and arent free to move

Question 8

Do simple molecular substances have high or low MP and BP - why

Answer 8

Low - weak van der Waals forces of attraction between molecules that dont take much energy to overcome

Question 9

Descrive macromolecular covalent bonding

Answer 9

Lattice of many atoms held together by strong covalent bonds

Question 10

Do macromolecular covalently bonded substances have high or low MP and BP - why

Answer 10

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

Question 11

Do substances with macromolecular covalent bonds conduct electricity

Answer 11

Most dont as all electrons are used in bonding

Question 12

Describe structure of diamond

Answer 12

3D tetrahedral structure of C atoms, with each C atom bonded to 4 others

Question 13

Describe structure of graphite

Answer 13

Macromolecular covalent - each C atom only bonded to 3 other C atoms
Weak van der Waals forces between layers so layers can slide over each other
Conducts electricity due to 1 delocalised electron from each C atom

Question 14

Describe metallic bonding

Answer 14

Lattice of positive metal ions strongly attracted to a sea of delocalised electrons
Malleable as layers can slide over each other

Question 15

Do metallic compounds have high or low BP and MP - why

Answer 15

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

Question 16

Do metallic compounds conduct electricity - why

Answer 16

Yes - delocalised electrons can move throughout the metal to carry charge

Question 17

How does strength of metallic bonds change across periodic table - why

Answer 17

Increases - higher MP and BP
Stronger charge on metal ions
More delocalised electrons per ion
Stronger force of attraction

Question 18

Define electronegativity

Answer 18

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

Question 19

What affects electronegativity

Answer 19

Nuclear charge
Atomic radius
Electron shielding

Question 20

Most electronegative element

Answer 20

Fluorine - largest nuclear charge for its electron shielding, small atomic radius

Question 21

How do you get non-polar bonds

Answer 21

Both bonding elements have the same electronegativities

Question 22

When do you get a polar bond

Answer 22

Bonding atoms have different electronegativities

Question 23

Strongest type of inter-molecular force

Answer 23

Hydrogen bonding

Question 24

Weakest type of inter-molecular force

Answer 24

van der Waals forces

Question 25

Describe van der Waals’ forces of attraction

Answer 25

Temporary dipoles are created by the random movement of electrons
Induces dipole in neighbouring molecule

Question 26

Are van der Waals forces greater in smaller or larger molecules

Answer 26

Larger - more electrons present

Question 27

Describe permanent dipole-dipole attraction

Answer 27

Some molecules with polar bonds have permanent dipoles

Forces of attraction between those dipoles and those of neighbouring molecules

Question 28

Why is ice less dense than liquid water

Answer 28

Liquid - hydrogen bonds constantly break and reform as molecules move about
Ice - Hydrogen bonds hold molecules in fixed position making them further apart from each other than in liquid water

Question 29

Dative covalent bond

Answer 29

Formed when an electron deficient atom/ion accepts a lone pair of electrons from another atom/ion with a free lone pair of electrons

Question 30

What does shape of molecules depend on

Answer 30

Number of electrons in the valence shell of the central atom

Number of these electrons which are in bonded or lone pairs

Question 31

What does the Electron Pair Repulsion Theory state

Answer 31

Electron pairs will take up positions as far away from each other as possible, minimise the repulsive forces between them

Question 32

Which experience the most repulsion;
Lone pair - Lone pair
Lone pair - Bonded pair
Bonded pair - Bonded pair

Answer 32

LP - LP = strongest repulsion
LP - BP = middlle repulsion
BP - BP = weakest repulsion

Question 33

Shape and bond angle of a shape with 2 bonded pairs and 0 lone pairs

Answer 33

Linear

180 degrees

Question 34

Shape and bond angle of shape with 3 bonding pairs and 0 lone pairs

Answer 34

Trigonal planar

120 degrees

Question 35

Shape and bond angle of shape with 4 bonded pairs and 0 lone pairs

Answer 35

Tetrahedral

109.5 degrees

Question 36

Shape and bond angle in a shape with 5 bonded pairs and 0 lone pairs

Answer 36

Trigonal bipyramid

90 and 120 degrees

Question 37

Shape and bond angles of shape with 6 bonded pairs and 0 lone pairs

Answer 37

Octohedral

90 degrees