7) Periodicity

Question 1

Define group

Answer 1

vertical column in the periodic table

Question 2

Elements in a group have _ and the same _

Answer 2

similar chemical properties

number of outer shell electrons

Question 3

Define period

Answer 3

horizontal row of elements in the periodic table

Question 4

Elements show _ across a period

Answer 4

a trend in properties

Question 5

Define periodicity

Answer 5

a repeating trend in properties of elements across each period

Question 6

Name the 4 block of the periodic table

Answer 6

s-block
p-block
d-block
f-block

Question 7

Define first ionisation energy

Answer 7

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

Question 8

Give an equation for the first ionisation energy of Na

Answer 8

Na(g) -> Na+ (g) + e-

Question 9

The first electron lost will be _ and will experience _

Answer 9

in the highest energy level

the least attraction from the nucleus

Question 10

What is nuclear attraction and therefore, ionisation energy affected by?

Answer 10

atomic radius
nuclear charge
electron shielding

Question 11

Define second ionisation energy

Answer 11

the energy required to remove 1 e- from each ion in 1 mole of gaseous 1+ ions of an element to form 1 mole of gaseous 2+ ions

Question 12

Give an equation for the second ionisation energy of He

Answer 12

He+ (g) -> He2+ (g) + e-

Question 13

What do successive ionisation energies provide important evidence for?

Answer 13

different energy levels

a large jump in ionisation energy marks a change from one shell to another

Question 14

What is the trend in first ionisation energy down a group and why?

Answer 14

first ionisation energy decreases

atomic radius increases and shielding increases

Question 15

What is the trend in first ionisation energy across a period and why?

Answer 15

first ionisation energy increases

nuclear charge increases

Question 16

Define metallic bonding

Answer 16

the electrostatic attraction between positive metal ions (cations) and delocalised electrons

Question 17

Define giant metallic lattice

Answer 17

3D structure of cations and delocalised electrons, bonded together by strong metallic bonds

Question 18

Describe a giant metallic lattice

Answer 18

cations fixed in position

mobile delocalised e- (from each atoms’ outer shell)

Question 19

Define giant covalent lattice

Answer 19

3D structure of atoms, bonded together by strong covalent bonds

Question 20

Give 3 elements which form a giant covalent lattice

Answer 20

carbon
boron
silicon

Question 21

Diamond has a _ structure and bond angles of _

Answer 21

tetrahedral

109.5

Question 22

Do giant metallic lattices conduct electricity?

Answer 22

yes in solid and liquid states (electrons act as mobile charge carriers)

Question 23

Do giant covalent lattices conduct electricity?

Answer 23

no except graphene and graphite

Question 24

What two properties do giant metallic lattices and giant covalent lattices share?

Answer 24

high melting and boiling points

insoluble

Question 25

Describe graphene and graphite

Answer 25

giant covalent structures of carbon based on planar hexagonal layers with bond angles of 120 degrees. This bonding only uses 3/4 outer electrons so the spare e- is delocalised

Question 26

State the difference between graphene and graphite

Answer 26

graphene is a single layer of graphite whereas, graphite is made up of parallel hexagonal layers with weak London forces between

Question 27

What does the sharp decrease in melting point across periods 2 and 3 indicate?

Answer 27

change from giant to simple molecular structures

Question 28

Why does Si form a giant structure and not a simple molecular lattice?

Answer 28

because it is in group 4 - the same as carbon, so behaves in the same way and forms a giant covalent structure like diamond