Atoms, elements and compounds

Question 1

State the relative charges and approximate relative

masses of protons, neutrons and electrons

Answer 1

Protons: +1 , 1
Neutrons: 0, 1
Electrons: -1, 1/2000

Question 2

Definition of atoms, elements, compounds

Answer 2

Atom: smallest type of particles
Elements: substance made out of 1 type of atom only
Compound: 2 or more elements chemically joined

Question 3

Use proton number and the simple structure of

atoms to explain the basis of the Periodic Table

Answer 3

• Elements are organised in order of increasing proton number
• Elements within a group/column have the same number of electrons in their outer shell
• Elements in group 0 have a full outer shell
• Across a period electrons are being added to the same valence (outer) shell

Question 4

Define isotopes

Answer 4

Atoms of an element with the same proton number but different nucleon number

Question 5

State one medical and one industrial use of

radioactive isotopes

Answer 5

• Medical:
  Yttrium-90: used to identify solid large tumours
• Industrial:
  Californium-252: used to inspect hidden explosives in luggage

Question 6

Describe an alloy

Answer 6

a mixture of a metal with other elements

Question 7

Formation of ions

Answer 7

by electron loss or gain

Question 8

Valency

Answer 8

the charge on an ion

Question 9

Describe the lattice structure of ionic

compounds

Answer 9

ionic bond= electrostatic attraction between oppositely charged ions => giant ionic lattices or
a regular arrangement of
alternating positive and negative ions

Question 10

Describe the formation of single covalent bonds in

H2, Cl2, H2O, CH4 and HCl

Answer 10

the sharing of pairs of electrons leading to the noble gas configuration

Question 11

Define alloptrope

Answer 11

different arrangements of the same element which can change its properties

Question 12

Describe the giant covalent structures of graphite and

diamond

Answer 12

Diamond:
- A carbon atom forms 4 covalent bonds with other carbon atoms. The atoms link together to form a giant lattice.
Graphite:
- Carbon atoms arranged in layers. Each carbon atom is joined to 3 other carbon atoms. Arranged in hexagon. Strong covalent bonding within layers. Weak bonding between layers
(pg38)

Question 13

Describe the similarity in properties
between diamond and silicon(IV) oxide,
related to their structures

Answer 13

• Forms very hard colourless crystals and has a high boiling and melting point. This is because it takes a lot of energy to break the strong covalent bonds

Question 14

Describe metallic bonding and use this to describe the electrical conductivity and malleability of metals

Answer 14

a lattice of positive ions in a ‘sea of electrons.

• Conduction is due to vibrations of the atoms passing energy to the next. Metallic structure allows the atoms to vibrate more freely. Delocalised electrons can carry energy through metallic structure quickly. However, the electrons will not move as readily through the lattice if atoms are vibrating faster
• Metals are malleable because when a force is applied, the layers of positive ions can slide over each other