periodicity

Question 1

1st ionisation energy

Answer 1

the energy required to remove one electron from each atom in a mole of gaseous atoms to form one mole of gaseous 1+ ions

Question 2

factors affecting ionisation energy

Answer 2

-atomic radius- distance and nuclear attraction
-nuclear charge- more protons= greater attraction between nucleus and outer electrons
-electron shielding- inner shell electrons repel outer shell electrons

Question 3

why is the second ionisation energy greater than the first

Answer 3

one the 1st electron is removed the 2nd electron is pulled closer to the nucleus, the nuclear attraction increases therefore more ionisation energy is required to remove the second electron

Question 4

trend in first ionisation energy down a group:

Answer 4

1st ionisation energy descreases because the atomic radius increases, there are more shells so shielding increases, nuclear attraction decreases

Question 5

the trend in 1st ionisation energy across a period:

Answer 5

1st ionisation energy increases because the nuclear charge increases, atomic radius decreases, so there is a stronger attraction between the nucleus and outer shell electrons

Question 6

why does the 1st ionisation energy tend to rise and fall across a period?

Answer 6

the first fall represents the filling of a new orbital, the next fall represents the pairing of electrons within an orbital

Question 7

metallic bonding:

Answer 7

in a solid metal structure each atom donates outer electrons into a delocalised pool, the positive ions left consist of the nucleus and inner electron shells

Question 8

properties of metals:

Answer 8

strong metallic bonds- attraction between positive ions and delocalised electrons
-high electrical conductivity
-high melting and boiling points

Question 9

explain conductivity in metals

Answer 9

can conduct electricity in solid and liquid states, the delocalised electrons can move through the structure and carry a charge

Question 10

explain the melting and boiling points of metals

Answer 10

metals have high melting and boiling points because high temperatures are needed to provide a large amount of energy needed to overcome the strong electrostatic attraction between cations and electrons

Question 11

properties of giant covalent lattices:

Answer 11

-high melting and boiling points
-insoluble
-not electrical

Question 12

why are graphite and graphene conductors of electricity?

Answer 12

only 3 electrons of carbon are involved in the bonding therefore the remaining electron is released into a pool of delocalised electrons