C1+ Atoms and Compounds

Question 1

What is an atom?

Answer 1

The smallest part of an element that can exist.

Question 2

What are all substances made of?

Answer 2

Atoms.

Question 3

How are atoms of each element represented?

Answer 3

By a chemical symbol, e.g. O for oxygen, Na for sodium.

Question 4

How many different elements are there approximately?

Answer 4

About 100 different elements.

Question 5

Where are elements shown?

Answer 5

In the periodic table.

Question 6

How are compounds formed?

Answer 6

From elements by chemical reactions.

Question 7

What do chemical reactions always involve?

Answer 7

The formation of one or more new substances and often a detectable energy change.

Question 8

What do compounds contain?

Answer 8

Two or more elements chemically combined in fixed proportions.

Question 9

How can compounds be represented?

Answer 9

By formulae using the symbols of the atoms from which they were formed.

Question 10

How can compounds be separated into elements?

Answer 10

Only by chemical reactions.

Question 11

What does the conservation of mass state?

Answer 11

During a reaction no mass is created or destroyed.

Question 12

How can chemical reactions be represented?

Answer 12

By word equations or equations using symbols and formulae.

Question 13

Why must equations be balanced?

Answer 13

To show there are the same number of reactant atoms as product atoms.

Question 14

Is mass lost or gained during a chemical reaction?

Answer 14

No, mass is not lost or gained.

Question 15

What happens if a gas is produced and escapes during a reaction?

Answer 15

It can appear that mass is lost.

Question 16

What is filtration?

Answer 16

Separating an insoluble solid and a liquid.

Question 17

What is a mixture?

Answer 17

Two or more elements or compounds not chemically combined together.

Question 18

What happens to the chemical properties of substances in a mixture?

Answer 18

They remain unchanged.

Question 19

Name physical processes that can separate mixtures.

Answer 19

Filtration, crystallisation, simple distillation, fractional distillation, chromatography.

Question 20

Do physical processes involve chemical reactions?

Answer 20

No, no new substances are made.

Question 21

What is a mixture?

Answer 21

Two or more different elements mixed together but not chemically combined (bonded).

Question 22

How does distillation work?

Answer 22

The mixture is heated; the liquid with the lower boiling point evaporates first, then is cooled, condensed, and collected.

Question 23

How does chromatography separate mixtures?

Answer 23

Some colours are more soluble and separate.

Question 24

What is fractional distillation used for?

Answer 24

To get petrol and fuels.

Question 25

What is chromatography used for?

Answer 25

Forensics.

Question 26

What does an alpha particle contain?

Answer 26

2 protons and 2 neutrons (a helium nucleus).

Question 27

What can new experimental evidence lead to?

Answer 27

A scientific model being changed or replaced.

Question 28

Before the electron was discovered, how were atoms thought of?

Answer 28

As tiny spheres that could not be divided.

Question 29

What did the plum pudding model suggest?

Answer 29

That the atom is a ball of positive charge with negative electrons embedded in it. (JJ Thompson)

Question 30

What did the gold foil experiment conclude about atoms?

Answer 30

The mass of an atom was concentrated at the centre (nucleus) and the nucleus was positively charged. (Rutherford)

Question 31

What model replaced the plum pudding model?

Answer 31

The nuclear model.

Question 32

How did Niels Bohr adapt the nuclear model?

Answer 32

By suggesting electrons orbit the nucleus at specific distances.

Question 33

What name was given to the positive particles in the nucleus?

Answer 33

Proton.

Question 34

Who provided evidence for the existence of neutrons?

Answer 34

James Chadwick.

Question 35

What is a subatomic particle?

Answer 35

A particle inside an atom.

Question 36

How many electrons are in an atom compared to protons?

Answer 36

The number of electrons equals the number of protons.

Question 37

Do atoms have an overall electrical charge?

Answer 37

No, atoms have no overall electrical charge.

Question 38

What is the atomic number of an atom?

Answer 38

The number of protons in an atom of an element.

Question 39

Do all atoms of an element have the same number of protons?

Answer 39

Yes.

Question 40

Do atoms of different elements have different numbers of protons?

Answer 40

Yes.

Question 41

What is the mass number of an atom?

Answer 41

The sum of the protons and neutrons in an atom.

Question 42

Mass of proton?

Answer 42

1

Question 43

Mass of neutron?

Answer 43

1

Question 44

Mass of electron?

Answer 44

0

Question 45

Charge of proton?

Answer 45

+1

Question 46

Charge of neutron?

Answer 46

0

Question 47

Charge of electron?

Answer 47

-1

Question 48

What are isotopes?

Answer 48

Atoms of the same element with the same number of protons but different numbers of neutrons.

Question 49

Can atoms of the same element have different neutrons?

Answer 49

Yes, these are called isotopes.

Question 50

What is the relative atomic mass of an element?

Answer 50

An average value that takes account of the abundance of the isotopes of the element.

Question 51

What is an ion?

Answer 51

An element that has lost or gained electrons.

Question 52

What ion charge do Group 1 elements make?

Answer 52

1+ ions (lose 1 electron).

Question 53

What ion charge do Group 2 elements make?

Answer 53

2+ ions.

Question 54

What ion charge do Group 3 elements make?

Answer 54

3+ ions.

Question 55

What ion charge do Group 7 elements make?

Answer 55

1- ions (gain 1 electron).

Question 56

What ion charge do Group 6 elements make?

Answer 56

2- ions.

Question 57

What ion charge do Group 5 elements make?

Answer 57

3- ions.

Question 58

What is the equation for atomic mass?

Answer 58

Ar = [(% of isotope a × mass of isotope a) + (% of isotope b × mass of isotope b)] ÷ 100