bonding and physical properties

Question 1

solid -arangment of particles

Answer 1

regular .crystal shapes have straight edges .solids have definite shapes

Question 2

solid-spacing

Answer 2

close -solids are not easily compressed

Question 3

solid-movement

Answer 3

vibrating around a point -diffusion is very slow , solids expand upon heating

Question 4

liquid-arrangement of particles

Answer 4

random -a liquid changed shape to fit the bottom of a container

Question 5

liquid-spacing

Answer 5

close -liquids are not easily compressed

Question 6

liquid-movement

Answer 6

rapid jolsting as diffusion is slow and liquids evaporate

Question 7

gas-arrangement of particles

Answer 7

random as a gas will fill its container

Question 8

gas-spacing

Answer 8

far apart as gases are easily compressed

Question 9

gas-movement

Answer 9

rapid as diffusion is rapid and gases exert pressure

Question 10

ionic compounds have strong electrostatic forces between….

Answer 10

oppisitley charged ions

Question 11

do ionic compounds have high or low melting points ? explain

Answer 11

high as they have strong electrostatic forces that extend throughout the whole structure. these require a lot of energy to break in order for the ions to move apart from each other

Question 12

do metallic crystals have a high or low melting point ? explain

Answer 12

high. attraction of positive to negative extended throughout the structure.strong metallic points

Question 13

what are molecular crystals ?

Answer 13

molecules held in a array of regular inter molecular forces .covalent bonds act between the atoms in a molecule but not between the molecules

Question 14

do molecular crystals have low or high melting points ?

Answer 14

low as inter molecular forces are much weaker than covalent ,ionic or metallic bonds

Question 15

give the properties of molecular crystals ?

Answer 15

crystals are soft and break easy
low melting temperatures
do not carry electricity as their are no charged particles to carry it

Question 16

what is a macromolecular crystal ?

Answer 16

A crystalline solid in which the atoms are all linked together by covalent bonds

Question 17

do macromolecular strucutures have high or low melting temp?

Answer 17

high as they have strong bonds

Question 18

what are diamond and graphite made up of ?

Answer 18

carbon , they are called allotropes of carbon

Question 19

explain the structure of diamond ?

Answer 19

pure carbon with covalent bonding between every carbon atom .bonds spread throughout the structure which is why it is a giant structure .each carbon atom has for covalent bond to the other carbons .The four electron pairs repel each other ,, tetrehedron shape (with bond angles of 109.5)

Question 20

explain the properties of diamond and give the reasons ?

Answer 20

a giant 3D shape with strong covalent bonds .
a very hard material
very high melting point
does not conduct electricity as their is no free charged particles to carry charge

Question 21

what is the bonding in graphite ?

Answer 21

strong covalent and weaker van waals forces

Question 22

explain the shape of molecules in graphite ?

Answer 22

each carbon atoms forms three other single covalent bonds to other carbon atoms .
form a flat trigonal arrangement. (sometimes called trigonal planar) ,120 .

Question 23

describe the structure of bonding ?

Answer 23

two dimensional linked hexagons. spare electron in p orbitals merge above and below the plane of the carbon atoms ,these electrons can move anywhere in the layer, so they are delocalised which adds to the strength of the bonding

Question 24

why does graphite conduct electricity ?

Answer 24

the delocalised electrons, they can travel freely in the material but only move along the hexagonal planes , not at right angles to them .

Question 25

what bonds hold the layers of carbon together in graphite ?why does this matter ?

Answer 25

weak van der waals forces. it means the layers of carbon can easily slide over each other which makes graphite soft flaky

Question 26

give the properties of graphite ?

Answer 26

soft material
very high melting point (due to strong network of covalent bonds which makes its a giant structure )
conducts electricity