Topic #2: Bonding and structure Flashcards Preview

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Flashcards in Topic #2: Bonding and structure Deck (29):
1

What are the 3 bond types?

Covalent- sharing electrons
Ionic- giving electrons
Metallic- pulled together by charges

2

When does each bond type occur?

Covelant- Nonmetal and Nonmetal
Ionic- Metal and Nonmetal
Metallic- Metals/alloys

3

Metals that lose electrons become _______ charged ions.

Positively

4

How are ionic compounds (giant ionic lattices) held together?

Strong electrostatic forces of oppositely charged ions

5

Can covalent bonds contain small molecules?

Yes

6

Are covelant bonds strong or weak?

Strong

7

Are polymers covelantly bonded?

Yes

8

What causes the strong metallic bonds?

Free to flow delocalised electrons

9

When do things change state of matter?

Freezing and melting at melting point
Boiling and condensing at the boiling point

10

How does the strength of the bonds affect melting points?

The stronger the bond, more energy is needed to break it (higher melting point)

11

List the 4 state symbols

g - gas
l - liquid
s - solid
aq - aqueous in solution

12

Why are ionic melting points so high?

Many very strong electrostatic forces of attraction are hard to break

13

Why can molten ionic compounds conduct electricity?

The ions are free to move

14

Are boiling points for small molecules high or low, and why?

Low, because only weak intermolecular forces need to be broken, not the covelant bonds.

15

How does molecule size impact intermolecular force strength?

The larger the molecules the stronger the bond

16

Do polymers have high or low melting points?

High- they are large molecules

17

What are the melting points for giant covelant structures like?

High, there are very strong bonds

18

Why are alloys harder than pure metals?

Different size atoms disrupt smooth slidy layers

19

Do all metals have high melting points?

No

20

Why are metals good conductors?

They can carry charge and energy in the delocalised electrons

21

Describe diamond's structure.

4 hexagonal carbon bonds, very strong, no conduction, high melting point, hard

22

Describe the structure of graphite.

3 Carbon bonds, with one delocalised electron per atom to carry charge. No bonds between layers, soft.

23

What are fullerenes?

Hexagonal carbon structures (can be rings of 5 or 7) made of carbons, useful in nanotechnology

24

What is graphene?

A single layer of graphite, useful in electronics

25

What are the size boundaries for nanoscience?

1-100 nm

26

What are the size of fine and coarse particles?

Fine, 100-2500 nm
Coarse, 2500-10000 nm

27

If the sides of a cube decrease by 10 times what does the surface area to volume ration increase by?

10 times

28

Why use nanoparticles over bulk metal?

Nanoparticles have larger surface areas, meaning less is needed, and they have different properties

29

What can nanoparticles be used for?

Suncreams, electronics, cosmetics, medicine, catalysts and deodorants