Chapter 2 - Bonding, Structures and Nanoparticles

Question 1

What group of atoms are found naturally unbonded ?

Answer 1

The noble gases

Question 2

Why are the noble gases unreactive ?

Answer 2

Because they have a full outer shell of electrons which is very stable

Question 3

What compounds are found in ionic bonding ?

Answer 3

a Metal and a non-metal

Question 4

What happens in an ionic bond ?

Answer 4

• electrons move from the metal to the non-metal

- each ion has filled a full outer shell

Question 5

What is the definition of an ionic bond ?

Answer 5

An ionic bond is the attraction between oppositely charged ions.

Question 6

What is the definition of a covalent bond ?

Answer 6

A covalent bond is a shared pair of electrons

Question 7

What is the definition of a molecule ?

Answer 7

A molecule is two or more atoms covalently bonded together

Question 8

What is the definition of diatomic ?

Answer 8

Diatomic means that there are two atoms covalently bonded in a molecule.

Question 9

What are the seven diatomic elements ?

Answer 9

Hydrogen (H2) , Nitrogen (N2), Fluorine (F2), Oxygen(O2), Iodine (I2) , Chlorine(Cl2), Bromine(Br2)

Question 10

What is a lone pair ?

Answer 10

A lone pair is unbonded pair of electrons

Question 11

Are covalent bonds strong ?

Answer 11

Covalent bonds are strong and require substantial energy to break them .

Question 12

What is the definition of metallic bonding?

Answer 12

Metallic bonding is the attraction between the positive ions in a regular lattice and the delocalised electrons.

Question 13

What is a metallic lattice ?

Answer 13

A metallic - lattice is a three-dimensional structure of positive ions and delocalised electrons bonded by metallic bonds.

Question 14

What are the physical properties of a metallic lattice ?

Answer 14

• good conductors of electricity
• metals usually have a high melting point
• metals are usually malleable and ductile

Question 15

What does malleable mean ?

Answer 15

malleable means a metal can be hammered into shape without breaking

Question 16

What does ductile mean ?

Answer 16

Ductile means the metal can be drawn into a wire

Question 17

Why are metals malleable and ductile ?

Answer 17

Metals are both because the layers of ions can slide over each other, yet the delocalised electrons still attract the ions and hold the structure together.

Question 18

What is an alloy?

Answer 18

An alloy is a mixture of two elements, at least one of which is a metal, and the resulting mixture has metallic properties.

Question 19

Why are alloys harder than pure metals?

Answer 19

some of their ions are different size to those of the metal. This distorts the layers of the structure and makes it more difficult for the layers to slide over each other.

Question 20

What is the equation for finding the % of gold in an alloy?

Answer 20

% of gold in an alloy = number of carats x 100
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Question 21

What is a giant ionic lattice ?

Answer 21

A Giant ionic lattice is a three-dimensional structure of oppositely charged ions held together by ionic bonds

Question 22

What are the physical properties of a giant ionic lattice ?

Answer 22

• High melting and boiling point
• soluble in water
• good conductors of electricity when molten/dissolved

Question 23

What is an aqueous solution ?

Answer 23

An aqueous solution is a solution in which the solvent is water

Question 24

What are the forces called that hold the separate molecules together in molecular covalent structures ?

Answer 24

Van der Waals’

Question 25

Are van der Waal forces strong or weak ?

Answer 25

weak require little energy to separate.

Question 26

What are the physical properties of Molecular Covalent ?

Answer 26

• low melting and boiling points
• do not conduct electricity
• insoluble in water

Question 27

What is a giant covalent structure ?

Answer 27

It is a three-dimensional structure of atoms that are joined by covalent bonds

Question 28

What is an allotrope ?

Answer 28

Allotropes are different forms of the same element, in the same stage.

Question 29

What are the three allotropes of carbon ?

Answer 29

Diamond , graphite and graphene.

Question 30

What are the physical properties of diamond ?

Answer 30

• high melting and boiling points
• does not conduct electricity
• very hard
• used in cutting tools

Question 31

What are the physical properties of graphite ?

Answer 31

• High melting and boiling point
• Good conductor of electricity
• soft
• used in lubricants for machinery

Question 32

What are the physical properties of graphene ?

Answer 32

• High melting and boiling points
• Good conductor of electricity
• Very strong
• future uses in solar cells and batteries

Question 33

What is a nanoparticle ?

Answer 33

A nanoparticle is a structure that is 1-100nm in size and consists of a few hundred atoms.

Question 34

Why do nanoparticles have different properties to their bulk material ?

Answer 34

This is due to their high surface area to volume ratio.

Question 35

Why are nanoparticles of zinc oxide now used in sun cream ?

Answer 35

• Give better skin coverage to the sun cream
• They give more effective protection from the UV rays
• They are clear and colourless
• They do not degrade on exposure to the sun

Question 36

What are the risks of using nanoparticles in sun cream ?

Answer 36

• potential cell damage in the body, they may be able to penetrate the cell membranes
• harmful effects on the environments