Bonding and Structures

Question 1

Name the three types of chemical bond

Answer 1

Ionic, covalent, metallic

Question 2

When does ionic bonding occur?

Answer 2

When a metallic element reacts with a non-metallic element

Question 3

How does an ionic bond form?

Answer 3

Metal atoms lose electrons to form positive ions, they transfer these to the atoms of non-metallic elements, which form negative ions

Question 4

What is an ionic bond?

Answer 4

An electrostatic force of attraction between oppositely charged ions

Question 5

When does metallic bonding occur?

Answer 5

In a metallic element or alloy, between the metal ions

Question 6

How does a metallic bond form?

Answer 6

Each ion contributes its outer electrons to a ‘sea’ of delocalised electrons, leaving behind positive ions in a lattice structure

Question 7

What is a metallic bond?

Answer 7

An electrostatic force of attraction between the positive ions in the lattice and the negative delocalised electrons

Question 8

When does covalent bonding occur?

Answer 8

When non-metallic atoms bond together. This can be during a reaction, or in the case of diatomic molecules, occur naturally

Question 9

How does a covalent bond form?

Answer 9

When the outer shells of two non-metallic elements overlap each other, causing a pair outer electrons to be shared between the bonding atoms

Question 10

What is a covalent bond?

Answer 10

The electrostatic force of attraction between the positively charged nuclei of the bonded atoms and the shared pair of electrons

Question 11

Why do atoms form bonds?

Answer 11

To achieve a full outer shell of electrons

Question 12

Describe and explain the melting and boiling properties of ionic compounds

Answer 12

High mp and bp because of the large amounts of energy required to break many strong bonds

Question 13

Describe and explain the electrical conductivity of ionic compounds

Answer 13

When melted or dissolved, they conduct electricity because the ions are free to move and a charge can flow

Question 14

Describe and explain the melting and boiling properties of small molecules

Answer 14

They only have weak forces of attraction BETWEEN the molecules, it is these that are overcome NOT the covalent bonds when the substance mealts or boils

Question 15

Describe and explain the melting and boiling properties of giant covalent structures

Answer 15

These are solids with high melting and boiling points. All the atoms are linked by strong covalent bonds. These many bonds must be overcome to melt or boil the substance.

Question 16

Explain why pure metals can be bent and shaped

Answer 16

The atoms are arranged in layers, which can slide over each other

Question 17

Explain why alloys are much harder than pure metals

Answer 17

The layers are distorted because the atoms are different sizes, preventing the layers sliding over each other

Question 18

Explain why metals are conductors of electricity

Answer 18

The delocalised electrons carry electrical charge through the metal

Question 19

Explain why metals are good heat conductors

Answer 19

Thermal energy is tranbferred by the delocalised electrons

Question 20

Describe the similarities and differences in the structures of diamond and graphite

Answer 20

Both made of carbon atoms
Both contain many strong covalent bonds
Diamond atoms each bond to 4 other atoms
Graphite each atoms bonds to 3 others with a sea of delocalised electrons between layers, there are no covalent bonds between the layers