covalent bonding

Question 1

define single covalent bond

Answer 1

contains a shared pair of electrons

Question 2

define a multiple covalent bond

Answer 2

shares multiple pairs of electrons

Question 3

what does a bond show in terms of electrons

Answer 3

a bond shows a shared pair of electrons between 2 atoms

Question 4

what is a lone pair of electrons shown as in lewis structures

Answer 4

lone pair of electrons is shown by 2 dots

Question 5

define compound oxyanion

Answer 5

negatively charged ions where oxygen is bonded to the central atom

Question 6

what do group 7 elements break when they are the central atom

Answer 6

the octet rule

Question 7

what do you do with the charge on ions with lone pairs on the central atom

Answer 7

if an oxygens put them charge on them if not put the charge on the central atom

Question 8

define dative covalent bond

Answer 8

both bonding electrons come from 1 element and is represented by an arrow
formed from atoms with a lone pair of electrons

Question 9

in diamond how many covalent bonds does each carbon atom form

Answer 9

4 covalent bonds

Question 10

what shape does diamond have and give the bond angle

Answer 10

tetrahedral

109.5

Question 11

in graphite how many covalent bonds does each carbon atom form

Answer 11

3 covalent bonds

Question 12

what molecular shape does graphite have and give the bond angle

Answer 12

trigonal planar

120 degrees

Question 13

why does graphite conduct electricity

Answer 13

due to its delocalised electrons which can travel freely and allowing graphite to conduct electricity along the hexagonal planes

Question 14

why is graphite used in pencils

Answer 14

the weak Van Der Waals forces allow the layers to slide over each other making graphite soft and flaky

Question 15

why do ionic compounds only conduct electricity when aqueous or molten

Answer 15

as the ions are free to move and carry charge through the structure

Question 16

define simple molecular structure

Answer 16

small groups of atoms held together by covalent bonding

Question 17

define macromolecular structure

Answer 17

large numbers of atoms are link in regular 3d arrangements by covalent bonds

Question 18

define giant ionic structure

Answer 18

a lattice of positive and negative ions surrounding each other

Question 19

define metallic structure

Answer 19

regular lattice of positively charged metal ions held together by a cloud of delocalised electrons

Question 20

Describe the structure and bonding in graphite and explain why the melting point of graphite is very high (5 marks)

Answer 20

layers of carbon atoms​

with 3 covalent bonds to each carbon atom​

Van der Waals forces between the layers​

lots of very strong covalent bonds need to be broken​

this requires lots of energy

Question 21

Explain why graphite is a good conductor of electricity
(3 marks)

Answer 21

1 spare electron per carbon atom ​

delocalised between layers​

can flow between layers and carry charge

Question 22

The diagram shows the arrangement of some of the water molecules in a crystal of ice. Give one reason why ice is less dense that water

Answer 22

Water molecules in ice are held further apart due to hydrogen bonds