1.3 Bonding

Question 1

What is ionic bonding?

Answer 1

+ the electrostatic force of attraction between oppositely charged ions formed by electron transfer

Question 2

What structure do ionic crystals have?

Answer 2

+ a giant lattice of ions

Question 3

Describe the strength and melting points of ionic bonds?

Answer 3

+ stronger and MP is higher when the ions are smaller/ have higher charges

Question 4

Why are positive ions smaller compared to their atoms?

Answer 4

+ it has one less shell of electrons and the ratio of
protons to electrons has increased
+ so there is greater net force on remaining
electrons holding them more closely

Question 5

Why are negative ions formed from groups 5-7 larger than the corresponding atoms?

Answer 5

+ it has more electrons than the corresponding
atom but the same number of protons
+ so the pull of the nucleus is shared over more
electrons and the attraction per electron is less,
making the ion bigger

Question 6

What is covalent bonding?

Answer 6

+ a shared pair of electrons

Question 7

What is dative covalent bonding?

Answer 7

+ forms when the shared pair of electrons in the
covalent bond come from only one of the
bonding atoms
+ aka co-ordinate bonding
+ e.g NH4+ , H30+ ,NH3 , BF3

Question 8

What is metallic bonding?

Answer 8

+ the electrostatic force of attraction between the positive metal ions and the delocalised electrons

Question 9

What are the main factors that affect the strength of metallic bonding?

Answer 9

1. Number of protons ~ the more protons the
   stronger the bond
2. Number of delocalised electrons per atom ~ the
   more delocalised electrons the stronger the
   bond
3. Size of ion ~ the smaller the ion, the stronger the
   bond

Question 10

How do vdws’ arise?

Answer 10

1. Uneven distribution of electrons creates a temporary dipole
2. Which induces dipole in neighbouring molecules