Combined Chemistry - 5.2 Flashcards Preview

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Flashcards in Combined Chemistry - 5.2 Deck (48)
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1
Q

What type of bond exists between metals and non-metals in a compound?

A

Ionic Bond

2
Q

What type of bond exists in non-metal elements and compounds?

A

Covalent Bond

3
Q

What type of bonding exists in metallic elements and alloys?

A

Metallic bonding

4
Q

What is the name for the electrons that are free to flow in metallic bonding?

A

Delocalised electrons

5
Q

What is the name for the forces that exist between ions in an ionic bond?

A

Electrostatic forces

6
Q

Q. In which type of bond are electrons shared?

Q. In which type of bond are electrons transferred?

A
  • Covalent bond (electrons shared)
  • Ionic bond (electrons transferred)
7
Q

When atoms gain or lose electrons to become ions, they will have the electron structure of what group of elements?

A

Noble gases

8
Q

Q. What charge do metal ions have?

Q What charge do non-metal ions (except Hydrogen) have?

A
  • Metal ions are positive
  • Non-metal ions are negative
9
Q

Describe how sodium and chlorine bond to form sodium chloride.

*this is just an example, you should be able to do this for any metal and non-metal.

A
  • The sodium atom loses one electron to become a sodium ion
  • The chlorine atom gains one electron to become a chloride ion
  • The positive sodium ion is attracted to the negative chloride ion to form sodium chloride.
10
Q

Draw dot and cross diagrams for the atoms and ions of the following elements:

a) Magnesium
b) Fluorine

*this is just an example, you should be able to do this for any element in Groups 1, 2, 6 & 7.

A
11
Q

What charge do the ions of elements in the following groups have?

a) Group 1
b) Group 2
c) Group 6
d) Group 7

A

a) Group 1: +
b) Group 2: 2+
c) Group 6: 2-
d) Group 7: -

12
Q

Describe the structure and bonding of an ionic compound.

A
  • Ionic bonding
  • Giant structure of ions
  • Lattice structure
  • Oppositely charged ions held together by electrostatic forces acting in all directions
13
Q

What type of bonding is represented by the diagrams below?

A

Ionic bonding

14
Q

What are the limitations of the following diagrams to represent ionic structures?

  • Dot and Cross
  • Ball and Stick
A
  • Dot and cross: Doesn’t show the structure of the ionic compound, the size or arrangement of ions.
  • Ball and stick: Suggests gap between ions which aren’t in fact there.
15
Q

Use the diagram to work out the empirical formula of the sodium chloride.

*this is just an example, you should be able to do this when given a diagram of any ionic compound.

A

By looking at the ratio of ions in the compound:

• Ratio of ions in compound 1:1

Or, to calculate using charges on ions

  • Charge on sodium ion +
  • Charge on chloride ion –

Answer: Formula of sodium chloride: NaCl

16
Q

Small molecules contain what type of bonds?

A

Covalent bonds

17
Q

What type of bonds exist in large molecules, such as polymers?

A

Covalent bonds

18
Q

Give three examples of giant covalent structures.

A
  • Diamond
  • Graphite
  • Silicon dioxide
19
Q

What type of bonding is represented by the following diagrams?

A

Covalent bonding

20
Q

What do the lines in the following molecule represent?

A

Single covalent bonds

21
Q

Draw dot and cross diagrams for the following molecules:

a) Hydrogen chloride
b) Methane

*these are examples, you should be able to also do this for nitrogen, hydrogen, chlorine, oxygen, water and ammonia

A
22
Q

What type of molecule is represented below?

A

Polymer

23
Q

Describe the structure and bonding in a metal.

A
  • Metallic bonding
  • Strong metallic bonds
  • Giant structure of metal atoms in regular pattern
  • Outer shell electrons are delocalised
24
Q

What type of bonding is represented by the diagram below?

A

Metallic bonding

25
Q

Name the changes of state represented by the letters a,b,c & d below:

A

a) Melting
b) Freezing
c) Boiling
d) Condensing

26
Q

Draw a particle model to represent the following states:

a) Solid
b) Liquid
c) Gas

A
27
Q

What is the relationship between the forces between particles and a substance’s melting and boiling points?

A

The stronger the forces between particles, the higher the melting and boiling points (or vice versa)

28
Q

Higher Q. What are the limitations of using the particle models below to represent solids, liquids and gases?

A
  • No forces between the particles are shown in the diagram
  • All particles are represented by spheres
  • All the spheres are solid and inelastic
29
Q

What do the following state symbols represent?

a) s
b) l
c) g
d) aq

A

a) Solid
b) Liquid
c) Gas
d) Aqueous

30
Q

Why do ionic compounds have high melting and boiling points?

A

Because a lot of energy is needed to break the many strong bonds.

31
Q

Why do molten or aqueous solutions of ionic compounds conduct electricity?

A

Ions are free to move so charge can flow

32
Q

Why do small molecules usually have relatively low melting and boiling points?

A
  • They have weak forces between molecules (intermolecular forces)
  • It is the intermolecular forces that are overcome, not the covalent bonds, when the substance boils.
33
Q

What happens to the size of intermolecular forces as the size of molecules increase?

A

The size of intermolecular forces increase (hence higher melting and boiling points for larger molecules)

34
Q

Can molecules conduct electricity? Give a reason for your answer.

A

No, because they have no overall electric charge.

35
Q

What state are most polymers at room temperature? Why?

A
  • Solid
  • Because they are large molecules, with strong intermolecular forces, hence relatively high melting and boiling points (compared with small molecules).
36
Q

What bonds must be overcome in order to melt or boil giant covalent structures?

A

The strong covalent bonds between the atoms

37
Q

Name the structures represented by the diagrams below:

A

a) diamond
b) graphite
c) silicon dioxide (silica)

38
Q

Diamond and graphite are made out of a single element. Name this element.

A

Carbon

39
Q

Do metals have high or low melting points and boiling points?

A

High melting and boiling points

40
Q

Describe how the arrangement of atoms makes pure metals soft.

A
  • Atoms arranged in layers
  • Layers slide easily over each other
41
Q

Describe how the arrangement of atoms in an alloy makes alloys harder than pure metal.

A
  • Different sized atoms
  • Layers distorted
  • Atoms can’t easily slide over each other
42
Q

Why are metals good conductors of heat and electricity?

A

They have delocalised electrons that can carry the charge (in terms of conducting electricity) or transfer energy (in terms of conducting heat)

43
Q

Describe the structure and bonding of Diamond.

A
  • Giant Covalent Structure
  • Each carbon forms four covalent bonds with other carbon atoms
44
Q

Describe the properties of Diamond

A
  • Hard
  • Very high melting point
  • Doesn’t conduct electricity
45
Q

Describe the structure and bonding of Graphite.

A
  • Giant covalent structure
  • Each carbon forms three covalent bonds with other carbon atoms
  • Forms layers of hexagonal rings
  • No covalent bonds between layers
  • One electron from each carbon atom is delocalised
46
Q

Q. What is graphene?

Q. Name two uses of graphene.

A
  • A single layer of graphite
  • Used in electronics and composites
47
Q

Q. What is the chemical formula of Buckminsterfullerene?

Q. What element are all fullerenes made from?

Q. Describe the structure of fullerenes.

A
  • C60
  • Carbon
  • Mostly hexagonal rings of carbon (will also have rings with 5 or 7 carbon atoms). Can be spherical or cylindrical in shape.
48
Q

What are cylindrical fullerenes called and why are they useful?

A
  • Nanotubes
  • They have a high length to diameter ratio making them useful for nanotechnology, electronics and materials.