Trends in the Periodic Table

Question 1

What is the atomic radius?

Answer 1

Distance between the centre of the nucleus to the outermost electron.

Question 2

What is the trend for atomic radius from left to right across a period?
What is the trend down a group?

Answer 2

From left to right atomic radius decreases.

From top to bottom atomic radius increases.

Question 3

Explain the trend of atomic radius going right.

Answer 3

As you move right you are adding one proton and electron, they are in the same energy level so screening is constant. The attractive forces increase which is why the atomic radius decreases across a period.

Question 4

Explain the trend of atomic radius moving down.

Answer 4

As you move down the group the valence electrons enter into higher energy levels. Increases screening. Decreases attractive forces. This is why atomic radius increases down a group.

Question 5

What is the ionic radius?

Answer 5

Distance from the centre of the ions nucleus to the outermost electron. Ionic radius is different to its parent atom.

Question 6

Positive ions are ……….. than their parent atoms.

Explain.

Answer 6

Positive ions (Cations) are smaller than their parent atoms.
Metals that have lost electron/s becoming positive. This increases the attractive forces experienced by electrons. Decreasing ionic radius.

Question 7

Negative ions are …………. than their parent atoms.

Explain.

Answer 7

Negative ions (Anions) are bigger than their parent atoms. Non-metal has gained electron/s becoming negative. This decreases the attractive forces experienced by the electrons. Increasing ionic radius.

Question 8

Ionic radius ……………. across a period for Cations.

Answer 8

Decreases.

Question 9

Ionic radius …………….. across a period for Anions.

Answer 9

Increases.

Question 10

The term for:
Any molecule consisting of only two atoms?
T/F: The atoms must be from the same element.

Answer 10

Diatomic molecule. (7)
H, N, O, F, Cl, Br, I
False. Diatomic molecules don’t have to be from the same element.
CO

Question 11

Names for:
Group 1
Group 2
Group 7
Group 8

Answer 11

Group 1: Alkali Metals
Group 2: Alkali-Earth Metals (Very reactive)
Group 7: Halogens ( Very reactive)
Group 8: Noble gases (inert, they are unreactive)

Question 12

Another name for semi-metals?

Answer 12

Metalloids

Question 13

Where are metals, semi-metals and non-metals found on the periodic table?

Answer 13

Metals: To the left, to the left
Semi-metals: Inbetween metals and non-metals.
Non-metals: Right

Question 14

Inbetween group 2 and group 3 are the…

Answer 14

Transition metals

Question 15

Definition of Ionisation energy

Answer 15

The energy needed to remove an electron from an atom/ion in the gas phase.

Question 16

T/F: The ionisation energy for one element is always the same.

Answer 16

False, the 2nd Ionisation energy is always larger than the first.

Question 17

Ionisation energy across a period?

Ionisation energy down a group?

Answer 17

Across a period: Increases

Down a group: Decreases

Question 18

Explain Ionisation energy across a period.

Answer 18

Increases.
As you move right atomic radius decreases. Electrons are experiencing a larger attractive force which means you’ll need a larger Ionisation energy.
Metals (left) want to give away electrons so Ionisation energy less.
Non-metals (right) want to gain electrons so Ionisation energy lots.

Question 19

Explain Ionisation energy down a group.

Answer 19

Decreases.

As you move down, valence electrons are in higher energy levels (more screening) so they are easier to remove.

Question 20

Why are there jumps in Ionisation Energy?

Answer 20

It’s much easier to remove a valence electron than a core electron.

Question 21

Definition of Electron Affinity.

Answer 21

The energy released when an atom gains an electron.

Question 22

What is the trend of electron affinity across a period?

Down a group?

Answer 22

Electron Affinity increases across a period.

Electron Affinity decreases down a group.

Question 23

What is the definition of Electronegativity?

Answer 23

Measure of the tendency of an atom to attract electrons to itself. (To bond)

Question 24

What is the trend of Electronegativity across a period?Explain.
What is the trend down a group?
Explain.

Answer 24

Electronegativity increases across a period (from left to right) As you move right atoms find it easier to hold on to a gained electron. Higher electronegativity.
Electronegativity decreases down a group. (from top to bottom) As you move down atoms are less likely to hold on to a gained electron. Lower electronegativity.

Question 25

What is the term for this definition?

The repetition of similar properties in chemical elements (indicated by their positioning on the Periodic Table)

Answer 25

Periodicity

Question 26

Trend for melting and boiling points?
HINT: They are the same.
Period and Group…

Answer 26

Melting and boiling points increase across a period up until group 14. From 15 to the Noble Gasses it decreases.
Melting and Boiling points decrease down a group.