Chapter 7 - Periodicity

Question 1

atomic number

Answer 1

(left to right)
it is arranged in order of increasing atomic numbers
every element has atoms with 1 extra electron (than the one before)

Question 2

groups

Answer 2

each element in a group has the same number of outer-shell electrons and similar properties

Question 3

periods and periodicity

Answer 3

the no. of period = number of highest energy electron shell in an element’s atom.

Question 4

groups 1 and 2 are what block

Answer 4

s block

Question 5

groups 3 - 12 are what block

Answer 5

d block

Question 6

groups 15 - 18 are what block

Answer 6

p block

Question 7

the bottom block is called

Answer 7

f block

Question 8

what are group 1 called

Answer 8

alkali metals

Question 9

what are group 2 called

Answer 9

alkaline earth metals

Question 10

what are group 3-12 called

Answer 10

transition elements

Question 11

what are group 15 called

Answer 11

pnictogens

Question 12

what are group 16 called

Answer 12

chalogens

Question 13

what are group 17 called

Answer 13

halogens

Question 14

what are group 18 called

Answer 14

noble gases

Question 15

what is first ionisation energy

Answer 15

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

Question 16

what is ionisation energy

Answer 16

how easily an atom loses electrons to form positive ions

Question 17

factors that affect the ionisation energies?

Answer 17

nuclear charge (the higher the no. of protons, the higher the attraction between the nucleus and the outer electrons)
atomic radius (increased distance to get to furthest shell, decreasing the attraction)
electron shielding (electrons repel each other, so its called the shielding effect, which reduces the attraction)

Question 18

what is the second ionisation energy

Answer 18

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

Question 19

give an example of ionisation energy using helium

Answer 19

He has 2 protons and 2 electrons. It loses the first electron and then the other electron actually gets a higher attraction from the proton. This means that the 2nd ionisation energy will be greater than the first.

Question 20

Explain a graph that shows ionisation energies

Answer 20

the ionisation energy from one shell to another changes dramatically.

Question 21

Trends of ionisation energy in a period

Answer 21

1. a general increase in first ionisation energy across a period.
2. a sharp decrease in F.I.E from the end of a period and the beginning of another.

Question 22

Explain the trend down a group

Answer 22

1. atomic radius increases
2. more inner shells so the amount of shielding increases
3. nuclear attraction decreases.
4. F.I.E decreases.

Question 23

Explain the trend across a period

Answer 23

1. Nuclear charge increase
2. Same shell
3. Nuclear attraction increases
4. Atomic radius decreases
5. F.I.E increases

Question 24

Sub-shell trends

Answer 24

Across a group, the ionisation energy will increase till a sub-shell is filled up, and then decrease slightly, then build up again.

Question 25

What is successive ionisation energy

Answer 25

An element generally has as many ionisation energies as the number of electrons the element has.

Question 26

What is metallic bonding

Answer 26

The molecules have a giant metallic structure Full of positively charged ions Surrounded by delocalised electrons. There are strong electrostatic forces of attraction that exist between the positively charged ions and the electrons