Nucleus

Question 1

Give an approximation for the radius of

an atom

Answer 1

1x10^-10 metres

Question 2

What are the three subatomic

constituents of an atom?

Answer 2

1. Proton
2. Neutron
3. Electron

Question 3

Where is most of the mass of an atom concentrated?

Answer 3

In the nucleus

Question 4

Approximately what proportion of the total radius of

an atom is the radius of the nucleus?

Answer 4

1/10,000

Question 5

Describe the arrangement of protons, neutrons and

electrons in an atom

Answer 5

● Protons and neutrons are found in the
atom’s nucleus
● Electrons are found in discrete energy
levels around the nucleus

Question 6

What type of charge does the nucleus of an atom

have? Why?

Answer 6

● Positive charge
● The nucleus contains protons and neutrons
● Protons have a positive charge
● Neutrons have no charge

Question 7

Give two ways that an atom’s electron arrangement

can be changed

Answer 7

1. Absorbing electromagnetic radiation

2. Emitting electromagnetic radiation

Question 8

Explain how an atom’s electron arrangement

changes when it absorbs EM radiation

Answer 8

● Electrons move to higher energy levels

● They move away from the nucleus

Question 9

Explain how an atom’s electron arrangement

changes when it emits EM radiation.

Answer 9

● Electrons move to a lower energy level

● They move towards the nucleus

Question 10

How does the ratio of electrons to protons in an atom

result in the atom having no overall charge?

Answer 10

● The number of protons is equal to the
number of electrons
● Protons and electrons have equal and
opposite charges, so charge cancels

Question 11

What do all forms of the same element have in

common?

Answer 11

The number of protons

Question 12

What is the name given to the number of protons in

an atom?

Answer 12

Atomic Number

Question 13

What is an atom’s mass number?

Answer 13

The total number of protons and

neutrons in the atom.

Question 14

What is an isotope of an atom?

Answer 14

An atom of an element that has a
different number of neutrons, but the
same number of protons.

Question 15

What property differs between isotopes of an

element?

Answer 15

The mass of the atom.

Question 16

How do atoms turn into positive ions?

Answer 16

● They lose one or more of their outer
electrons
● Electrons are negatively charged, so
the resultant charge of the atom is
positive

Question 17

What are the relative masses of a proton, neutron

and electron?

Answer 17

● 1 - proton
● 1 - neutron
● 1/1836 - electron

Question 18

What is the relative charge of a proton?

Answer 18

+ 1

Question 19

What is the relative charge of an

electron?

Answer 19

-1