Chapter 7 - Periodic Trends In Structure And Bonding

Question 1

What is the one constant property of all metals?

Answer 1

Their ability to carry charge

Question 2

Give the definition of metallic bonding.

Answer 2

The strong electrostatic attraction between cations and delocalised electrons

Question 3

In a solid metal structure, what does each metal atom do with its negative outer shell electrons?

Answer 3

The atom donated the negative outer shell electrons to a shared pool of electrons which are delocalised throughout the whole structure

Question 4

Describe the difference in movement of the cations and the delocalised electrons.

Answer 4

Cations are fixed in position - maintaining structure and shape of the metals
The delocalised electrons are mobile and are able to move throughout the structure

Question 5

What is a structure of billions of metals atoms held together by metallic bonding called?

Answer 5

Giant metallic lattice

Question 6

Give three properties of metals

Answer 6

Strong metallic bonds
High electrical conductivity
High melting points and boiling points

Question 7

Explain why electrical conductivity is high in a metal when a voltage is applied across it

Answer 7

The delocalised electrons are able to move through the structure and carry charge

Question 8

Explain why most metals have high melting and boiling points

Answer 8

The melting point is dependent on the strength of the metallic bond.
High temperatures are needed to provide the large amount of energy needed to overcome the strong electrostatic attraction between the cations and electrons

Question 9

Why are metals not soluble?

Answer 9

They do not dissolve, instead they react with water/ polar substances

Question 10

Which non-metals form giant covalent lattices?

Answer 10

Boron, carbon and silicon

Question 11

What shape is the structure of silicon and carbon when it is bonded to 4 other atoms?

Answer 11

Tetrahedral

Question 12

What are all the bond angles in a diamond structure?

Answer 12

109.5°

Question 13

Why do giant covalent lattices have high melting points?

Answer 13

They have strong covalent bonds which require high temperatures to provide a large amount of energy needed to break the strong covalent bonds

Question 14

Why are giant covalent bonds insoluble in almost all substances?

Answer 14

There covalent bonds are far too strong to be broken down by interaction with solvents

Question 15

Why can’t carbon (diamond) and silicon conduct electricity?

Answer 15

Their four outer shell electrons are bonded so there isn’t an electron available to conduct electricity

Question 16

Why can graphite and graphene conduct electricity?

Answer 16

They both have a delocalised electron which is able to move through the giant covalent structure and carry charge

Question 17

What allows the melting point of a substance to be predicted?

Answer 17

The strength of the metallic bond which depends on
- the charge of an atom
- the ionic radius

Question 18

Which has a higher melting point, sodium or potassium?

Answer 18

Sodium has a higher melting point because it has a stronger metallic bond. Higher e- density of delocalised electron cloud. This is because the sodium has the same charge as it donates only one electron however it has a smaller ionic radius.