C1 - Atomic Structure

Question 1

Define the word element.

Answer 1

A substance made up from only one type of atom.

Question 2

Define the word atom.

Answer 2

The smallest part of an element that can exist.

Question 3

Define the word compound.

Answer 3

A substance made of two or more elements chemically bonded.

Question 4

Define the word molecule.

Answer 4

A small group of atoms covalently bonded.

Question 7

What is the difference between a pure element, a compound and a mixture?

Answer 7

A pure element contains only one type of atom (with the same atomic number)
A compound contains two or more elements chemically bonded together.
A mixture contains two or more different substances that are not chemically bonded together.

Question 8

Name the four main people who made models of the structure of the atom. Give their name, year they made the model, and the model they developed.

Answer 8

Ancient Greeks, 500-400BC, ideas about atoms and particles (spheres)
John Dalton, 1800s, atoms were small, hard spheres, each belonging to a chemical element and having a different mass.
JJ Thomson, 1900s, Plum Pudding Model (sphere of positively charged mass with small negatively charged electrons in and around its surface)
Ernest Rutherford, 1900s (after Thomson), shot alpha (dense and positive) particles at a sheet of gold, some passed through while some rebounded. This meant atoms were largely empty space and only the centre was positive (repelled positive particles). Called the Nuclear Model.
Niels Bohr, 1914, electrons orbit the nucleus at set levels/shells

Question 10

What is the structure of an atom?

Answer 10

A dense nucleus of neutrons and protons, with electrons orbiting around it.

Question 11

What do the periods and groups indicate about their elements?

Answer 11

Elements in the same period have the same number of energy levels.
Elements in the same group have the same number of valence electron.

Question 12

What are the relative charges of the subatomic particles?

Answer 12

Proton +1
Electron -1
Neutron 0

Question 13

What are the masses of the subatomic particles?

Answer 13

Proton 1amu
Neutron 1amu
Electron 1/2000amu

Question 14

What is the average radius of an atom?

Answer 14

0.1nm

1 * 10^-9m

Question 15

What is the radius of the nucleus?

Answer 15

1/10,000 that of an atom

Question 16

What overall charge do atoms have?

Answer 16

None (neutral)

Question 17

How many of each subatomic particle is in the following element?

16
O
Oxygen
8

Answer 17

Protons - 8
Electrons - 8
Neutrons - 8

Question 18

Define the term monatomic element.

Answer 18

Consisting of single atoms
Very stable
(e.g. Noble Gases, Group 0)

Question 19

Define the term diatomic elements.

Answer 19

Consisting of molecules (sharing valence electrons)
Formula written as symbol₂
Form a 7 on the Periodic Table (+ Hydrogen)

Question 20

Define the term polyatomic element.

Answer 20

Consisting of multiple atoms chemically bonded.

Question 21

Define the term ion.

Answer 21

Ions are charged particles.

Question 22

Define the term isotope.

Answer 22

Atoms of an element that have the same number of protons, but different numbers of neutrons.

Question 23

Describe an isotope in terms of the atomic model.

Answer 23

The number of electrons and protons remains the same, but there are more or less neutrons in the central nucleus.

Question 24

Why do ions have a charge?

Answer 24

Ions are atoms which have either gained or lost an electron. There is then no proton, or too many, to cancel out the charges for a neutral charge, leaving the ion with a positive or negative charge.

Question 25

How many of each subatomic particle is in this ion?

23
Na +
Sodium +
11

Answer 25

Proton - 11
Neutron - 12
Electron - 10

Question 26

How many of each subatomic particle is in this ion?

32
S 2-
Sulphur 2-
16

Answer 26

Proton - 16
Neutron - 16
Electron - 18

Question 27

Why doesn’t chlorine have a whole mass number?

Answer 27

It is an isotope; the mass number displayed on the periodic table is an average of the possible masses.

Question 28

Where in an atom are electrons found?

Answer 28

In the energy levels.

Question 29

What re the maximum number of electrons in the first three energy levels?

Answer 29

2, 8, 8,

Question 30

Why do elements is the same group react in a similar way?

Answer 30

They all have the same number of valence electrons.

Question 31

How many protons are in this element, and what is its electronic structure?

31
P
Phosphorus
15

Answer 31

Protons - 15

Structure - 2, 8, 5

Question 32

Predict the reaction of caesium with water, considering lithium and sodium’s reactions with water:

• Produces Hydrogen
• Floats
• Increasingly vigorous

Answer 32

Caesium will likely be extremely reactive with water, exploding on contact and producing hydrogen.

Question 33

What particles are involved in ionic bonding?

Answer 33

Electrons are lost / gained by the metal / non-metal.

Question 34

What particles are involved in covalent bonding?

Answer 34

Electrons are shared by two non-metals.

Question 35

Describe how (23) sodium (11) becomes a cation.

Answer 35

As it needs to lose one electron for a full, stable outer shell, it forms a bond with a non-metal, chloride. It loses its valence electron, which is gained by the chloride atom, which needs one more electron for a full valence shell. This creates a sodium ion (positive) and a chloride ion (negative).