(a) Periodicity

Question 1

How are the elements in the periodic table arranged?

Answer 1

In order of increasing atomic number.

Question 2

A vertical line of elements in the periodic table is referred to as a what?

Answer 2

Group.

Question 3

A horizontal line of elements in the periodic table is referred to as a what?

Answer 3

Period.

Question 4

Describe metallic bonding.

Answer 4

Metallic bonding consists of positive metal ions surrounded by a sea of delocalised electrons.

Question 5

Are metallic bonds: Strong or weak?
High or low melting point?
Good or bad energy conductors?

Answer 5

Strong
High
Good.

Question 6

What is the properties of a metallic bond which allows it to conduct energy?

Answer 6

It has delocalised electrons which are free to move.

Question 7

What is a covalent network?

Answer 7

Thousands of atoms which are held together by covalent bonds.

Question 8

Are covalent bonds: Strong or weak?
High or low melting point?
Good or bad conductors?

Answer 8

Strong
High
Bad.

Question 9

Why do covalent networks have high melting and boiling points?

Answer 9

It is the covalent bonds which have to break in order for them to melt.

Question 10

What are some examples of covalent networks?

Answer 10

Silicon, Boron, and carbon in the form of graphite or diamond.

Question 11

What is a covalent molecule?

Answer 11

Compounds held together by covalent bonds but which are intermolecularly bonded by van Der walls.

Question 12

Are covalent molecules: Strong or weak?
High or low melting points?
Good or bad conductors?

Answer 12

Weak
Low
Bad.

Question 13

Why do covalent molecules has low melting points?

Answer 13

It is the weak intermolecular (London dispersion) forces which break when the molecule melts rather than the strong covalent bonds.

Question 14

What are some examples of covalent molecules?

Answer 14

Diatomic molecules, Phosphorous, Sulphur, and fullerenes.

Question 15

What are the states which covalent molecular substances can be found?

Answer 15

Solid and gas.

Question 16

What are some examples of covalent molecules which are usually found as a gas?

Answer 16

Hydrogen, Nitrogen, Oxygen, Chlorine e.c.t.

Question 17

What are some examples of covalent molecules which are usually found as a solid?

Answer 17

Phosphorous, Sulphur, and fullerenes.

Question 18

What is the formula for phosphorous and sulphur?

Answer 18

P4 and S8.

Question 19

Why are some covalent molecules solids at room temperature?

Answer 19

They have more LDF’s between the molecules.

Question 20

What group in the periodic table are monatomic?

Answer 20

Group 8.

Question 21

What does it mean if an atom is monatomic?

Answer 21

It consists of one single unbounded atom.

Question 22

What hold monatomic atoms together?

Answer 22

London dispersion forces.

Question 23

Are monatomic compounds: Strong or weak?
High or low melting points?
Good or bad conductors?

Answer 23

Weak
Low
Bad.

Question 24

Why are group 8 atoms monatomic?

Answer 24

They have a full outer electron shell.

Question 25

What is the covalent radius?

Answer 25

The covalent radius is the measure of the size of an atom.

Question 26

Going across a period what happens to the covalent radius and why?

Answer 26

It decreases because the nuclear charge increases Burt the number of occupied energy levels remains the same and so the outer electrons and held more tightly.

Question 27

Going down a group what happens to the covalent radius?

Answer 27

It increases because the nuclear charge remains the same but there are more occupied energy levels and so there is more shielding of the nuclear charge and so the outer electrons are held more weakly.

Question 28

What is the definition of electronegativity?

Answer 28

The measure of attraction for electrons in a covalent bond.

Question 29

What happens to the electronegativity as it goes across a period and why?

Answer 29

Increases because the nuclear charge increases, and so the atom attracts bonded electrons more strongly.

Question 30

What happens to the electronegativity going down a period and why?

Answer 30

The number of filled electron shells increases and this creates more shielding of the nuclear charge, meaning that the electrons are less strongly attracted to the nucleus and so the electronegativity decreases going down a period.

Question 31

Where in the electronegativity scale would you find the atoms with the greatest electronegativity?

Answer 31

Top right.

Question 32

Where in the electronegativity scale would you find the atoms with the lowest electronegativity?

Answer 32

Bottom left.

Question 33

What is ionisation energy?

Answer 33

The amount of energy required to remove one mole of electron from one mole of gaseous atom.

Question 34

What happens to the ionisation energy going down a group and why?

Answer 34

It decreases going down a group because the outer electron is in an energy level furthest away from the nucleus, this means that the nuclear charge that is holding this electron is weaker. There are also more energy levels shielding the nuclear charge and so less energy is required.

Question 35

What happens to the ionisation energy going across a period and why?

Answer 35

It increases because the nuclear charge increases and so the attraction from the nucleus to the outer electron is stronger, this makes it more difficult to remove the outer electron and so more energy is required.