Periodicity

Question 1

How is the periodic table organised

Answer 1

In increasing atomic number

Question 2

Give the definition of ionisation energy

Answer 2

The energy required to remove one mole of electrons from one mole of gaseous atoms (under standard conditions).

Question 3

Give the general first ionisation energy equation of a metal

Answer 3

M (g) –> M^+(g) + e^-

Question 4

Give the general second ionisation energy equation of a metal

Answer 4

M^+ (g) –> M^2+(g) + e^-

Question 5

What happens to the ionisation energy of group 1 alkali metals as you go down the group and why

Answer 5

Reactivity increases down the group because as you go down the group the atoms get bigger and so there is a greater distance between he outermost shell and the nucleus

Question 6

Is the 2nd ionisation energy higher or lower than the 1st - why

Answer 6

Higher because the overall charge on the atom is more positive. There is greater attraction and hold over the electron being removed than before, requiring more energy to overcome.

Question 7

Across a period, what is the general trend in ionisation energy? Give two reasons

Answer 7

Increases
-Increase in nuclear charge along group
-BUT same shell (distance from nucleus) so shielding remains fairly constant

Question 8

How can you identify an element from a graph of its successive ionisation energies?

Answer 8

How many ionisation energies there are before the initial jump gives you the group of the element. The number of levels give you the period that the element is in.

Question 9

What are the four ‘blocks’ of the periodic table, and how many electrons do each hold?

Answer 9

S - 2
P - 6
D - 10
F - 14

Question 10

What are the names of the groups below the periodic table?

Answer 10

Lanthanides
Actinides

Question 11

What elements are metalloids (list/circle on periodic table)

Answer 11

B, SI, G, As, Sb, Te, Po

Question 12

Is Zinc a transition metal?

Answer 12

No - it has a full d-shell

Question 13

Why is the Be 1st I.E more than the B?

Answer 13

Electron configuration

the fifth electron in boron is in the 2p subshell, which is further away from the nucleus than the 2s subshell of beryllium.

Question 14

Why is the N 1st I.E more than the O?

Answer 14

The paired electrons in the 2p subshell of oxygen repel each other, making it easier to remove an electron in oxygen than nitrogen.

Question 15

Ionisation energy trend down a group (three reasons)

Answer 15

Decreases
-More shielding between outermost electron being removed and positive nucleus
-Bigger distance due to more shells

Question 16

What is electron affinity?

Answer 16

The energy released when 1 mole of gaseous atoms each acquire an electron to form 1 mole of gaseous ions.

Question 17

General trend of electron affinity down the group

Answer 17

Decreases
As you go down the group there are more shells and shielding and so it is harder for the electron to be attracted by the nucleus

Question 18

General trend of atomic radius across the period

Answer 18

Decreases because nuclear charge increases, pulling the electron shells closer

Question 19

General trend of atomic radius down the group

Answer 19

Increases due to the increasing number of shells

Question 20

Ionic radii compared to atomic radii in atoms that form positive ions

Answer 20

smaller (electrons lost)

Question 21

Ionic radii compared to atomic radii in atoms that form negative ions

Answer 21

bigger (electrons gained)