C2.5 - R* Explaining trends

Question 1

What factors do you consider, when explaining trends in reactivity?

Answer 1

When explaining trends in reactivity, the factors you consider are the:

1. Size of the atom
2. Shielding effect of inner electrons
3. Nuclear charge

Question 2

As you go down a group in the periodic table, the number of shells occupied by electrons does what?

Answer 2

As you go down a group in the periodic table, the number of shells occupied by electrons increases by one extra electron shell per period

Question 3

The number of shells occupied by electrons increasing by 1 as you go down a group means what?

Answer 3

The number of shells occupied by electrons increasing by 1 as you go down a group means that the atoms become larger going down any group

Question 4

What effects does the atoms becoming larger going down any group have?

Answer 4

The atoms becoming larger going down any group means that larger atoms:

1. Lose electrons more easily going down a group
2. Gain electrons less easily going down a group

Question 5

Why do larger atoms lose electrons more easily going down a group and larger atoms gain electrons less easily going down a group?

Answer 5

Larger atoms lose electrons more easily going down a group and larger atoms gain electrons less easily going down a group, because the:

1. Negatively charged outer electrons are further away from the attractive force of the positively charged nucleus
2. Inner shells of the electrons ‘screen,’ or ‘shield’ the outer electrons from the positive charge of the nucleus

Question 6

Why is the nucleus positively charged?

Answer 6

The nucleus is positively charged, because of its positively charged protons

Question 7

Why does reactivity increase as you go down group 1 in relation to the size of the atom?

Answer 7

Reactivity increases as you go down group 1, because the atoms get larger as you go down the group

Question 8

Why does reactivity increase as you go down group 1 in relation to the shielding effect?

Answer 8

Reactivity increases as you go down group 1 because the outer electron experiences a shielding effect from inner shells of electrons

Question 9

Why does reactivity increase as you go down group 1 in relation to the nuclear charge?

Answer 9

Reactivity increases as you go down group 1, because the size of the positive charge on the nucleus becomes larger as you go down a group, as more protons are present inside the nucleus

Question 10

What does the change from Li to Li+ take than Na changing to Na+?

Answer 10

The change from Li to Li+ takes more energy than Na changing to Na+

Question 11

What happens when group 7 elements react?

Answer 11

When group 7 elements react, their atoms gain an election in their outermost shell (highest energy level)

Question 12

When group 7 elements react, their atoms gain an election in their outermost shell (highest energy level).
What happens going down the group?

Answer 12

Going down the group, the outermost shell’s electrons get further away from the attractive force of the nucleus

Question 13

When group 7 elements react, their atoms gain an election in their outermost shell (highest energy level).
Going down the group, the outermost shell’s electrons get further away from the attractive force of the nucleus, so it is harder to attract and gain an extra incoming electron.
What will the outer shell also be?

Answer 13

The outer shell will also be shielded by more inner shells of electrons

Question 14

Going down group 7, what is the effect of the increased nuclear charge (which helps atoms gain an incoming electron) outweighed by?

Answer 14

Going down group 7, the effect of the increased nuclear charge (which helps atoms gain an incoming electron) is outweighed by the effect of:

1. Increased distance
2. Shielding by more inner electrons

Question 15

Going down group 7, the effect of the increased nuclear charge (which helps atoms gain an incoming electron) is outweighed by the effect of increased distance and shielding by more inner electrons.
So chlorine is less reactive than what?

Answer 15

Chlorine is less reactive than fluorine

Question 16

Chlorine is less reactive than fluorine.

What is the attraction for the incoming electron when F changes to F- much greater than?

Answer 16

The attraction for the incoming electron when F changes to F- is much greater than when Cl changes to Cl-

Question 17

Reactivity increases as you go down group 1, because the atoms get larger as you go down the group, so the single electron in the outermost shell (highest energy level) is what?

Answer 17

Reactivity increases as you go down group 1, because the atoms get larger as you go down the group, so the single electron in the outermost shell (highest energy level) is attracted less strongly to the positive nucleus

Question 18

Reactivity increases as you go down group 1, because the atoms get larger as you go down the group, so the single electron in the outermost shell (highest energy level) is attracted less strongly to the positive nucleus.
The electrostatic attraction with the nucleus gets what?

Answer 18

The electrostatic attraction with the nucleus gets weaker

Question 19

Reactivity increases as you go down group 1, because the atoms get larger as you go down the group, so the single electron in the outermost shell (highest energy level) is attracted less strongly to the positive nucleus
Why does the electrostatic attraction with the nucleus gets weaker?

Answer 19

The electrostatic attraction with the nucleus gets weaker, because the distance between the:
1. Outer electron
2. Nucleus
increases

Question 20

Reactivity increases as you go down group 1 because the outer electron experiences a shielding effect from inner shells of electrons.
This reduces what?

Answer 20

This reduces the attraction between the:

1. Oppositely charged outer electron
2. Nucleus

Question 21

Reactivity increases as you go down group 1, because the size of the positive charge on the nucleus becomes larger as you go down a group, as more protons are present inside the nucleus.
This suggests what?

Answer 21

This suggests that the attraction for the outer electron should get stronger

Question 22

Reactivity increases as you go down group 1, because the size of the positive charge on the nucleus becomes larger as you go down a group, as more protons are present inside the nucleus.
This suggests that the attraction for the outer electron should get stronger, but what outweighs the increasing nuclear charge?

Answer 22

This suggests that the attraction for the outer electron should get stronger, but the:
1. Greater distance
2. Shielding effect of inner electrons
outweighs the increasing nuclear charge

Question 23

Going down the group, the outermost shell’s electrons get further away from the attractive force of the nucleus, so it is harder to do what?

Answer 23

Going down the group, the outermost shell’s electrons get further away from the attractive force of the nucleus, so it is harder to:
1. Attract
2. Gain
an extra incoming electron

Question 24

When group 7 elements react, their atoms gain an election in their outermost shell (highest energy level).
Going down the group, the outermost shell’s electrons get further away from the attractive force of the nucleus, so it is harder to attract and gain an extra incoming electron.
The outer shell will also be shielded by more inner shells of electrons, again reducing what?

Answer 24

The outer shell will also be shielded by more inner shells of electrons, again reducing the electrostatic attraction of the nucleus for an incoming electron