Unit 1

Question 1

How is the Periodic Table organised.

Answer 1

By Atomic Number - Top Left to Bottom Right

Question 2

Why are chemicals arranged in groups?

Answer 2

As the elements in a group have similar chemical properties. E.g. Group 8 are all unreactive.

Question 3

What are the Metals in the first 20 elements?

Answer 3

Lithium (Li), Sodium (Na), Magnesium (Mg), Beryllium (Be), Aluminium (Al), Potassium (K), Calcium (Ca)

Question 4

What are the Covalent Networks in the first 20 elements?

Answer 4

Carbon Graphite (Cgraphite), Carbon Diamond (Cdiamond), Silicon (Si), Boron (B)

Question 5

What are the Covalent Molecules in the first 20 elements?

Answer 5

Hydrogen (H2), Oxygen (O2), Fluorine (F2), Chlorine (Cl2), Nitrogen (N2), Phosphorus (P4), Sulfur (S8), Fullerene (C60)

Question 6

What are the Monatomics in the first 20 elements?

Answer 6

Helium (He), Neon (Ne), Argon (Ar)

Question 7

Describe Metal’s Bonding and Structure.

Answer 7

It contains METALLIC BONDS - which is the electrostatic force of attraction between positive nuclei and delocalised electrons.
A Metal has a 3-D metallic LATTICE shape.

Question 8

What properties does a metal commonly have?

Answer 8

High melting and boiling points.
Conduct heat and electricity.
Are a solid at room temperature.

Question 9

Describe a covalent network Bonding and Structure.

Answer 9

A network contains covalent bonds which occur when NON-METALS SHARE electrons.
The electrostatic attraction exists between the positive nucleus and shared electrons.
Covalent networks have a 3-D network structure.

Question 10

Why is graphite’s structure different to other covalent networks?

Answer 10

It consists of layers of hexagons. Between these layers are weak forces of attraction (L.D.Fs).
This is different to normal 3-D tetrahedral arrangements like Diamond. This arrangement of atoms is much stronger and makes it much harder. (Boron and Silicon are similar).

Question 11

What properties does a covalent network commonly have?

Answer 11

High melting and boiling points - because strong covalent bonds are being broken.
They don’t conduct electricity (with the exception of graphite).
They are insoluble in water because networks are NON-POLAR COVALENT.

Question 12

Describe covalent molecules Bonding and Structure.

Answer 12

The bonding is the same as a covalent network (covalent bonds arise between non-metals sharing electrons).
The structure is either a diatomic molecule (H2, N2, O2 eg.)
P4 has a pyramidal/ tetrahedral shape.
S8 has a cyclic structure.
C60 (fullerene) is a sphere.

Question 13

What properties does a covalent molecule commonly have?

Answer 13

The diatomic molecules all exist as gases due to their low melting and boiling points.
P4, S8, C60 are all molecular solids.
This is because if there are more electrons there are more LDFs. This means more energy is required to break these forces.

Question 14

Describe a monatomic Bonding and Structure.

Answer 14

There are no bonds - Only weak intermolecular forces (aka Van Der Waals forces) called L.D.Fs.
The structure is a single atom only as it is monatomic.

Question 15

What properties does a monatomic commonly have?

Answer 15

They are unreactive.
Have low melting and boiling points and are gases.
They are insoluble and don’t conduct.

Question 16

Describe covalent radius.

Answer 16

Covalent radius is the distance from the nucleus to the outer most energy level.
As we move left to right in a period this decreases. This is because the atomic number is increasing. We describe this as the NUCLEAR CHARGE increasing. This greater the positive nuclear charge attracts the electrons more therefore making the atom smaller.
The covalent radius also increases down a group. This is because an energy level is being added each time.

Question 17

Describe ionisation energy.

Answer 17

It is the energy required to remove one mole of electrons in the GASEOUS STATE. You get the equation in the data book:
E(g) -> E+(g) + e- 1st ionisation energy.
E+(g) -> E2+(g) + e- 2nd ionisation energy.
Etc…

Question 18

Describe ionisation energy in a period and a group.

Answer 18

Across a period the ionisation energy increasing because:
The increasing nuclear charge which means there is a greater force of attraction between nucleus and electrons.
The decreasing covalent radius means the electrons are closer to the nucleus.

Down a group the ionisation energy decreases because:
The increasing covalent radius due to an energy level being added each time, the force of attraction is decreasing.
The inner shells SHEILD the outer most electrons from the nuclear charge.

Question 19

Describe electronegativity.

Answer 19

It is the force of attraction an atoms nucleus has on BONDING electrons.
It is dependent on two things: Nuclear Charge and Atomic size (covalent radius). If an atom is small and has lots of protons then it is very electronegative.

Question 20

Describe electronegativity in a period and a group.

Answer 20

Electronegativity increases across a period.
Electronegativity decreases down a group.
This means fluorine is the most electronegative atom in the PT (4.0).

Question 21

Describe Ionic Bonding in Compounds.

Answer 21

It begins between metal and non-metal IONS which have either gained or lost electrons.
This is a strong bond.
They have a 3-D lattice shape, this is made up of thousands of ions so the ionic formula uses a RATIO of ions. (Eg NaCl is 1:1)

Question 22

Describe the properties of Ionic Bonding.

Answer 22

Most of them are soluble in water, because water is ‘polar covalent’. Polar covalent substances are partially charged, whereas ionic compounds are fully charged.
This means ionic compounds will dissolve in polar compounds since LIKE DISSOLVES LIKE.
They only conduct electricity when MOLTEN or in SOLUTION, this means they do NOT conduct as a solid. (They conduct because the bonds have been broken and the IONS are free to move).
They usually have high mp/bp because their strong bonds require a lot of energy.
Most are colourless (white) unless they contain a Transition Metal.

Question 23

Describe Covalent Bonding in Compounds.

Answer 23

A covalent bond is a STRONG bond, formed between NON-METALS. (As it is compounds, they have to be different non-metals).
The bond holds the atoms because the shared electrons are attracted to the positive nucleus. (In an ELEMENT these electrons would be shared EQUALLY eg. H2).

Question 24

Describe Non-Polar Covalent bonds.

Answer 24

A non-polar covalent bond happens if the elements in a compound have the same electronegativity (e/n value) eg. NCl

Question 25

Describe Polar Covalent bonds.

Answer 25

E