Bonding, Structure and Properties of Matter

Question 1

What does the sign (aq) mean

Answer 1

aqueous (dissolved in water)

Question 2

What is an ionic bond

Answer 2

The ionic bond is a strong electrostatic force of attraction between the positive metal ion and the negative non-metal ion

Question 3

Describe what happens when two atoms of sodium react with one molecule of chlorine

Answer 3

• Sodium belongs to Group 1 of the periodic table. It has one electron in its outer shell
• Chlorine belongs to Group 7 of the periodic table. It has seven electrons in its outer shell
• One chlorine molecule contains two chlorine atoms
• Each sodium atom transfers one electron to one of the chlorine atoms
• All four atoms now has eight electrons in their outer shell
• The atoms become ions Na+ and Cl-
• The compound formed is sodium chloride, NaCl

Question 4

how are ionic compounds held together and why do they only conduct electricity when in solution

Answer 4

• held together by strong electrostatic forces of attraction so have high melting and boiling points
• as the charged ions are free to move about an carry their charge

Question 5

What is a metallic bond

Answer 5

the attraction between the positive ions and the delocalised negatively charged electrons

Question 6

what makes metals good thermal and electrical condutors

Answer 6

the delocalised electrons can move around freely and transfer energy

Question 7

what is an alloy

Answer 7

mixtures that contain a metal and at least one other element

Question 8

what makes alloys stronger than pure metals

Answer 8

the added element disturbs the regular arrangement of the metal atoms so the layers do not slide over each other so easily

Question 9

what does the amount of carbon determine about steels properties

Answer 9

• high carbon content makes it hard and strong

- low carbon content makes it soft and easily shaped

Question 10

what is a covalent bond

Answer 10

a shared paired of electrons between atoms occurring in non-metallic elements

Question 11

In order for chlorine to bond with another chlorine atom what must happen

Answer 11

• an electron from each atom is shared

- this gives both atoms a full 8 outer shell electrons

Question 12

Diamond is a from of carbon, describe its properties

Answer 12

• It has a giant, rigid covalent structure (lattice)

- Each carbon atom form four strong covalent bonds with other carbon atoms

Question 13

Graphite is a form of carbon, describe its properties

Answer 13

• Each carbon atom form three covalent bonds with other carbon atoms
• This results in a layered, hexagonal structure

Question 14

why is graphite soft and slippery

Answer 14

The layers are held together by weak intermolecular forces meaning they can slide past eachother

Question 15

Describe the structure of buckminsterfullerene

Answer 15

• consists of 60 carbon atoms
• the atoms are joined together in a series of hexagons and pentagons
• it is the most symmetrical, and therefore, the most stable fullerene

Question 16

what is a purpose of buckminsterfullerene

Answer 16

carbon nanotubes are useful for nanotechnology and electronics

Question 17

what is the min diameter of coarse particles

Answer 17

1 x 10”-5m

Question 18

what is the diameter of fine particles

Answer 18

100nm to 2500nm

Question 19

what is the diameter of nanopartivles

Answer 19

1nm to 100nm

Question 20

why are nanoparticles good for suncream / concerns

Answer 20

• they provide better skin coverage and are more effective and protecting skin from the suns harmful rays
• they are so small there are concerns they cold get into and damage human cells

Question 21

why are smaller quantities needed to achieve required properties of nanoparticles

Answer 21

the atoms can be placed into exactly the right position