Bonding, Structure and Properties of Matter

Question 1

What is an ionic compound

Answer 1

A giant structure of ions, held together by strong electrostatic forces of attraction.

Question 2

What is Covalent bonding

Answer 2

Covalent bonding is when atoms share one or more pairs of electrons. Occurs within non metals.

Question 3

What is metallic bonding

Answer 3

The bonding in a metal consists of positive ions (atoms that have lost electron(s)) and delocalized electrons arranged in a regular pattern. Occurs in metallic elements and alloys.

Question 4

What is a compound

Answer 4

substances in which 2 or more elements are chemically combined.

Question 5

What is Ionic bonding

Answer 5

Metal + Non metal: electrons in the outer shell of the metal atom are transferred. Metal atoms lose electrons to become positively charged ions. Non-metals gain electrons to become negatively charged ions.

Question 6

What are the three states of matter

Answer 6

Solid, Liquid and Gas. Melting and freezing take place at the melting point. Boiling and condensing take place at the boiling point.

Question 7

What are limitations of the simple particle model

Answer 7

Limitations of the simple model include that in the model there are no forces, that all particles are represented as spheres and that the spheres are solid.

Question 8

What are some properties of ionic compounds

Answer 8

• Ionic compounds have regular structures (giant ionic lattices) in which there are strong electrostatic forces of attraction in all directions between oppositely charged ions.
• They have high melting and boiling points, because a lot of energy is required to break the many strong bonds.
• When melted and dissolved in water, ionic compounds conduct electricity because the ions are free to move and carry current.

Question 9

What are properties of small molecules

Answer 9

• Substances that consist of small molecules are usually gases or liquids that have low boiling and melting points.
• They have weak intermolecular forces between the molecules. These are broken in boiling or melting.
• They do not conduct electricity, because small molecules do not have an overall electric charge.

Question 10

Giant covalent structures

Answer 10

• Substances that consist of giant covalent structures are solid with very high melting points.
• All of the atoms in these structures are linked to other atoms by strong covalent bonds.
• These bonds must be overcome to melt of boil these substances.

Question 11

What are properties of Metals

Answer 11

• Metals have giant structures of atoms with strong metallic bonding.
• Most metals have high melting and boiling points.
• The layers of atoms in metals are able to slide over each other, so metals can be bent and shaped.

Question 12

What are the properties of Alloys

Answer 12

• Alloys are made from 2 or more different types of metals.
• The different sized atoms distort the layers in the structure, making it harder for them to slide over each other. So alloys are harder than pure metals.

Question 13

How are metals as conductors

Answer 13

-Good conductors of electricity because the delocalized electrons in the metal carry electrical charge through the metal. This it the same for thermal energy.

Question 14

Explain the properties of diamond

Answer 14

In diamond, each carbon is joined to 4 other carbons covalently. It’s very hard, has a high melting point and does not conduct electricity.

Question 15

Graphite

Answer 15

• In graphite, each carbon is covalently bonded to 3 other carbons, forming layers of hexagonal rings which have no covalent bonds between the layers.
• The layers can slide over each other due to no covalent bonds, meaning that graphite is soft and slippery.
• One electron from each carbon atom is delocalized. This makes graphite similar to metals, because of its delocalized electrons.

Question 16

What is a delocalized electron

Answer 16

Electrons that are not associated with a particular atom.

Question 17

Fullerenes

Answer 17

-As well as diamonds and graphite, carbon can also form fullerenes, which can form cage-like structures and tubes, based on hexagonal rings of carbon atoms.

Question 18

Graphene

Answer 18

• Is a single layer of graphite.
• Has properties that make it useful in electronics and composites.
• Graphene is very strong because atoms within its layers are very tightly bonder and it is also elastic because the planes of atoms can flex relatively easily without the atoms breaking apart.

Question 19

What are examples of uses of fullerenes

Answer 19

• They can be used as lubricants, to deliver drugs in the body and catalysts.
• Nanotubes can be used for reinforcing materials, for example tennis rackets

Question 20

What is the Nanoscience.

Answer 20

Nanoscience is the study of small particles that are between 1-100 nanometers in length.

Question 21

What is different about the properties of nanoparticles

Answer 21

A nanoparticle has different properties to the ‘bulk’ chemical it’s made from, because of their high surface area to volume ratio. It may also mean that smaller quantities are needed to be effective than for materials with normal particle sizes.

Question 22

What are some uses of nanoparticles

Answer 22

• They have a high surface area to volume ratio, and therefore would make good catalysts.
• Nanotubes could make stronger, lighter building materials.
• New cosmetics. Sun tan cream and deodorant. They make no white marks.

Question 23

What is an disadvantage of nanoparticles.

Answer 23

-There are some concerns that nanoparticles may be toxic to people. They may be able to enter the brain from the bloodstream and cause harm