Topic 2 Bonding, Structure And Properties Of Matter Flashcards
(85 cards)
1
Q
What does ionic bonding occur between?
A
Metals and non-metals
2
Q
What does covalent bonding occur between?
A
Non-metals
3
Q
Where does metallic bonding occur?
A
In metallic elements and alloys
4
Q
What are the electrostatic forces of attraction between in an ionic compound?
A
Oppositely charged ions
5
Q
What is an ionic compound?
A
Giant structure of ions
6
Q
What arrangement do the ions form in an ionic compound?
A
Regular lattice
7
Q
What is the structure of an ionic compound called?
A
Giant ionic lattice
8
Q
What are the 2 properties of ionic compounds?
A
- High melting and boiling points
- can conduct electricity when melted/dissolved in water
9
Q
Why can ionic compounds conduct electricity when melted or dissolved in water?
A
Ions free to move - can carry charge/charge can flow
10
Q
Why are covalent bonds strong?
A
positively charged nuclei of the bonded atoms are attracted to shaired pair of electrons by electrostatic forces
11
Q
How does the displayed formula represent covalent bonds?
A
as single lines between atoms
12
Q
What is a simple molecular substance?
A
made up of molecules containing a few atoms joined by covalent bonds
13
Q
What is the formula for ammonia?
A
NH3
14
Q
What are 8 examples of simple molecular substances?
A
- hydrogen
- chlorine
- oxygen
- nitrogen
- methane
- water
- hydrogen chloride
- ammonia
15
Q
What are 3 ways covalent bonds can be represented?
A
- dot and cross diagrams
- displayed formula
- 3D model
16
Q
What are the atoms within molecules in simple molecular substances held together by?
A
very strong covalent bonds
17
Q
What are the forces of attraction between molecules in simple molecular substances?
A
intermolecular forces
18
Q
What forces are overcome when a simple molecular substance is melted or boiled?
A
intermolecular forces
19
Q
Why do simple molecular substances have low melting and boiling points?
A
weak intermolecular forces are easily overcome
20
Q
What state are simple molecular substances usually in at room temperature?
A
gases or liquids
21
Q
Why do molecular compounds not conduct electricity?
A
not charged so there are no free electrons or ions
22
Q
Why do larger molecules have higher melting and boiling points?
A
as molecules get bigger, the strength of intermolecular forces increases
23
Q
What are 3 bulk properties of simple molecular substances?
A
- usually gases/liquids at room temp
- don’t conduct electricity
- low melting and boiling points
24
Q
What are polymers?
A
long chains of repeating units
25
What are the **atoms** in **polymer molecules joined by**?
**strong covalent bonds**
26
Why are most **polymers solids** at **room temp**?
**larger intermolecular forces** between **polymer molecules** than between **simple covalent molecules** so **more energy** needed to **break** them
27
What are all the **atoms** in **giant covalent structures bonded together by**?
**strong covalent bonds**
28
Why do **giant covalent structures** have **very high melting and boiling points**?
**lots of energy** needed to **break strong covalent bonds**
29
What are **3 examples** of **giant covalent structures**?
- **diamond**
- **graphite**
- **silicon dioxide**
30
In **diamond**, how many **covalent bonds** does each **carbon atom form**?
**4** covalent bonds
31
What are **3 properties** of **diamond**?
- **very hard**
- **very high melting point**
- **doesn't conduct electricity**
32
Why is **diamond very hard**?
**carbon atoms** each form **4 covalent bonds**
33
Why does **diamond not conduct electricity**?
**no free electrons or ions**
34
Why does **diamond** have a **very high melting point**?
**strong covalent bonds** take **a lot of energy** to **break**
35
In **graphite**, how many **covalent bonds** does each **carbon atom form**?
**3** covalent bonds
36
In **graphite**, what do the **3 covalent bonds** each **carbon atom forms, create**?
**layers** of **carbon atoms** arranged in **hexagons**
37
Why can the **layers** in **graphite move over each other**?
**no covalent bonds between layers** - held together **weakly**
38
Why is **graphite** a **good lubricating material**?
its **soft** and **slippery** (**layers can slide over eachother**)
39
Why has **graphite** got a **high melting point**?
**covalent bonds** in **layers** need **lots of energy to break**
40
In **graphite**, why does **each carbon atom** have **one delocalised electron**?
**only 3** out of **carbons 4 outer electrons** are used in **bonds**
41
Why does **graphite conduct electricity** and **thermal energy**?
**each carbon atom** has **one delocalised electron** that can **move and carry charge**
42
What **property** of **graphene** makes it **useful** in **electronics**?
Contains **delocalised electrons**- can **conduct electricity** through **whole structure**
43
What **property** of **graphene** makes it **useful** to add to **composite materials**?
**Strong covalent bonds** - **very strong** but also **light**
44
What are **fullerenes**?
**Molecules of carbon** with **hollow shapes**
45
What was the **first fullerene** to be **discovered**?
**Buckminsterfullerene**
46
What **shape** does **Buckminsterfullerene** have?
**Hollow sphere**
47
What is the **molecular formula** of **Buckminsterfullerene**?
**C(60)**
48
What is the **structure** of **fullerenes**?
Mainly made up of **hexagonal rings** of **carbon atoms** but can also contain **pentagons** and **heptagons**
49
Why are **fullerenes useful** in **delivering drugs** into the **human body**?
**Fullerenes** can **’cage’** other **molecules**
50
Why do **fullerenes** make **great industrial catalysts**?
**huge surface area**- **Individual catalyst molecules** can be **attached**
51
What are **3 examples** of **uses** of **fullerenes**?
- **deliver drugs** into the **body**
- **make lubricants**
- **make industrial catalysts**
52
What are **carbon nanotubes**?
**Tiny carbon cylinders (fullerenes)**
53
What are **4 properties** of **carbon nanotubes**?
- **very high length** to **diameter ratio**
- **conduct electricity**
- **conduct heat**
- **high tensile strength** (don’t break when stretched)
54
What is **nanotechnology**?
**Technology** that uses **very small particles** such as **nanotubes**
55
What are **3 examples** of **uses** of **nanotubes**?
- in **nanotechnology**
- in **electronics**
- to **strengthen materials** (eg **tennis rackets**)
56
Why are **nanotubes useful** in **strengthening materials**?
**Don’t add much weight**
57
What do **metals consist of**?
**Giant structures** of **atoms** arranged in a **regular pattern**
58
Which **electrons** are **delocalised** and **free to move around** in **metals**?
**Outer shell electrons** of the **metal atoms**
59
What is **metallic bonding**?
**Strong electrostatic attraction** between **sea of negative delocalised electrons** and **positive metal ions**
60
What **holds** the **atoms** of a **metal together** in a **regular structure**?
**Electrostatic forces of attraction**
61
Are **metallic bonds strong** or **weak**?
**Very strong**
62
What are **2 substances** that are **held together** by **metallic bonding**?
**metallic elements** and **alloys**
63
Why are **most metals solid** at **room temperature**?
Have **high melting** and **boiling points**
64
What do **most metals** have **high melting** and **boiling points**?
**Strong metallic bonds**- **lots of energy** to be **broken**
65
Why are **metals good conductors** of **electricity**?
**Delocalised electrons carry charge** through **whole structure**
66
Why are **metals good conductors** of **thermal energy (heat)**?
**Energy transferred** by **delocalised electrons**
67
Why are **most metals malleable**?
**Layers of atoms** can **slide over each other**- **metals** can be **bent** or **shaped**
68
Why are **pure metals mixed** with **other metals**?
**Too soft** for **many uses** so **mixed** with **other metals** to **make alloys** which are **harder**
69
What are **alloys**?
**Mixture** of **two or more metals** or a **metal** and **another element**
70
Why are **alloys harder** than **pure metals**?
- **different elements** have **different sized atoms**
- **new metal atoms distort layers** of **metal atoms**- **harder** for **layers** to **slide over each other**
71
What are the **2 limitations** of the **particle theory model**?
- there are **no forces shown** (**no way of knowing their strength**)
- **particles represented** as **solid inelastic spheres** (instead of **atoms, ions or molecules**)
72
What are the **categories particles** are **put in based on**?
Their **diameter**
73
What are the **diameters** of **nanoparticles**?
**1-100nm**
74
What is **nanoscience**?
**area of science** that **investigates uses** and **properties** of **nanoparticles**
75
What are the **diameters** of **fine particles**?
**100-2500nm**
76
What are the **diameters** of **coarse particles**?
**2500-10000nm**
77
What are **coarse particles also referred to as**?
**Dust**
78
What is the **main property** of **nanoparticles**?
**Large surface area to volume ratio**
79
What happens to the **surface area** as **particles decrease** in **size**?
**Surface area increases** in **relation** to their **volume**- **surface area to volume ratio increases**
80
What is the **equation** to find the **surface area to volume ratio**?
**Surface area to volume ratio = surface area/volume**
81
What is the **rule for surface area to volume ratio** as **particles decrease in size**?
As the **side of a cube** is **decreased** by **factor of 10**, **surface area to volume ratio increases** by **factor of 10**
82
What **causes** the **properties** of a **material** to be **different** if it’s a **nanoparticle** rather than **in bulk**?
**Nanoparticles** have a **high surface area to volume ratio**
83
Why are **smaller quantities** of a **material made up of nanoparticles needed** to work as an **effective catalyst** than for **materials made up of ‘normal’ sized particles**?
**Nanoparticles** have a **high surface area to volume ratio**
84
What are **6 applications** of **nanoparticles**?
- as **catalysts**
- in **medicine**
- in **electronics**
- in **cosmetics**
- in **sun creams**
- in **deodorants**
85
What is a **disadvantage** of **nanoparticles**?
**Effects** of **nanoparticles** on **human health isn’t fully understood**
