C3 Structure and Bonding

Question 1

What is ionic bonding and where does it occur?

Answer 1

Ionic bonding occurs between metal and non metal atoms and they contain oppositely charged ions held together by electrostatic forces of attraction

Question 2

How is sodium chloride a ionic compound and what structure does it contain?

Answer 2

It is ionic compound as it made up of Na+ and Cl- ions. Sodium loses an electron whilst chlorine gains an electron to produce ions with a full outer electron shell. This forms a ionic lattice structure with a cubic shape and a giant repeating pattern. It is a giant ionic structure

Question 3

Name 5 common compound ions and there charges

Answer 3

OH- hydroxide
NO3 - Nitrate
NH4+ - Ammonium
SO4 2- Sulfate
CO3 2- Carbonate

Question 4

What are the features of ionic compounds?

Answer 4

High melting point due to strong forces of electrostatic attraction so a lot of energy is needed to break these bonds

Conducts electricity when molten or dissolved in solutions as ions are free to move round

Question 5

What is covalent bonding?

Answer 5

CB is the sharing of the outer electron in order for an atom to obtain a full shell.

Question 6

What type of charges do covalent bonds contain?

Answer 6

Electrostatic attraction between shared electrons and positive nucleus

Question 7

What is a dative covalent bond/Coordinate bond?

Answer 7

It is one atom donate 2 electrons to an atom or ion to form a bond

Question 8

Name a example of a compound which contains a coordinate bond?

Answer 8

NH4+

Question 9

Name 2 types of Giant covalent structures

Answer 9

Graphite and Diamond

Question 10

How is Graphite bonded and what are the features?

Answer 10

Each Carbon is bonded 3 times with the 4th electron being delocalised containing lots of strong covalent bonds. The layers slide easily due to weak forces between layers. It can conduct electricity as the delocalised electron can carry a charge. It has a low density and soluble

Question 11

How is Diamond bonded and what are the features?

Answer 11

Each carbon is bonded 4 times in a tetrahedral shape and it is tightly packed and rigid. It is a great conductor of heat and contains a very high melting point. It does not contain electricity as there are no delocalised electrons

Question 12

How are shapes of molecules determined?

Answer 12

The shape of a molecule is determined by the number of electron pairs around the central atom. Each electron pair naturally repels each other so that the largest bond angle exists between covalent bonds

Question 13

Name all the molecule shapes and bond angles?

Answer 13

Linear 180
V shaped 104.5
Trigonal planar 120
Triangular pyramid 107
Tetrahedral 109.5
Trigonal bipyramid 90 and 120
Octahedral 90

Question 14

Name a compound for each molecule shape?

Answer 14

Linear - BeCl2
V shaped - H2O
Trigonal planar - BF3
Triangular pyramid - NH3
Tetrahedral - CH4
Trigonal Bipyramid - PCl5
Octahedral - SF6

Question 15

What is electronegativity?

Answer 15

It is ability of an atom to attract electrons towards itself in a covalent bond

Question 16

Bigger the difference in electronegativity

Answer 16

More polar the bond

Question 17

Why is H2O polar?

Answer 17

Due to uneven distribution

Question 18

What is the order of IMF in order of decreasing weakness?

Answer 18

Hydrogen bonding
Permanent dipole dipole forces
VDW

Question 19

What are VDW forces?

Answer 19

They are the weakest IF force actings as a induced dipole dipole between molecules

Question 20

What are permanent dipole forces?

Answer 20

This force acts between polar bonds. The delta + and delta - regions attract each other and hold each other in a lattice like structure

Question 21

What is hydrogen bonding and name a compound where it occurs?

Answer 21

This is the strongest type of IF and these bonds form between hydrogen and the three electronegative atoms nitrogen oxygen and fluorine. Water is a example

Question 22

How does metallic bonding occur?

Answer 22

They contain giant metallic lattice structures held together by electrostatic forces of attraction between + metal ions and - delocalised electrons. Positive metal ions are surrounded by a sea of delocalised electrons

Question 23

Features of Compounds that contain metallic bonds?

Answer 23

High MP due to strong esf
Good electrical conductor due to sea of delocalised electrons
Good thermal conductors as delocalised electron can transfer ke