covalent bonding and halogens

Question 1

definition of covalent bonding

Answer 1

electrostatic attraction between shared electrons and a nuclei

Question 2

what type of atoms do covalent bonding associate with

Answer 2

non-metals

Question 3

what is the relative melting point of covalent bonds

Answer 3

low

Question 4

why is the melting point low for covalent bonds

Answer 4

• breaking IMF
• IMFs are very weak and need little energy to break

Question 5

are covalent bonds able to conduct electricity

Answer 5

no, no charged particles are ever able to move

Question 6

how is mass related to melting point

Answer 6

bigger mass = stronger IMF which means more energy needed to break IMFs so higher melting point

Question 7

example of giant covalent structures

Answer 7

graphite, diamond

Question 8

do giant covalent have high melting points

Answer 8

yes as you are breaking covalent bonds and they are very strong and need a lot of energy to break

Question 9

structure of graphite

Answer 9

• layers of carbon atoms bonded together
• each carbon forms 3 bonds and each atom has an electron left over so is delocalised

Question 10

can graphite conduct electricity

Answer 10

yes as one electron is delocalised so can move

Question 11

what can graphite be used as

Answer 11

lubricant

Question 12

why can graphite be used as lubricant

Answer 12

• between layers are IMF
• IMF are very weak and can be broken very easily
• layers are able to slide over each other
• graphite is very slippery and can be used as lubricant

Question 13

structure of diamond

Answer 13

forms a pyramid ( tetrahedron ) each C bonded to 4 others

Question 14

can diamond conduct electricity

Answer 14

no as all electrons were used in bonds

Question 15

does diamond have a higher or lower mpt than graphite

Answer 15

higher because more bonds are broken so even more energy is needed

Question 16

how many electrons do Halogens want to gain a full outer shell

Answer 16

1 e

Question 17

describe the trend of mpt going down the group the halogens

Answer 17

mpt increases because molecules get bigger so more IMF and more energy is needed

Question 18

describe the trend of colour going down the group of Halogens

Answer 18

gets darker

Question 19

describe the trend of reactivity going down the group of Halogens

Answer 19

reactivity decreases because
- atoms want gain an electron
- atoms get bigger going down the group and bigger atoms means greater distance between extra e and nucleus
- less electrostatic attraction
- less reactive

Question 20

give two experiments to prove that reactivity decreases

Answer 20

• reacting each metal with MG
• displacement reactions

Question 21

what does a pale green solution indicate after displacing halogens

Answer 21

chlorine has been displaced

Question 22

what does a orange solution indicate after displacing halogens

Answer 22

bromine has been displaced

Question 23

what does a purple solution indicate after displacing halogens

Answer 23

iodine has been displaced

Question 24

what colour is flourine

Answer 24

pale yellow gas

Question 25

what colour is chlorine

Answer 25

green gas

Question 26

what colour is bromine

Answer 26

brown liquid

Question 27

what colour is idodine

Answer 27

dark grey solid

Question 28

what colour is astatine

Answer 28

black solid

Question 29

what is the test for chlorine

Answer 29

place a damp piece of blue litmus paper in the chlorine and it will bleach it white