1b.2 The atom

Question 1

Name the three subatomic particles, along with their relative mass and relative charge.

Answer 1

Proton: relative mass 1, relative charge +1

Neutron: relative mass 1, relative charge 0

Electrons: relative mass 0.0005, relative charge -1

Question 2

What is the radius of an atom (in metres)

Answer 2

1 x 10^(-10) metres

Question 3

What particles does the nucleus of an atom contain?

Answer 3

Protons and neutrons

(Hydrogen is an exception - only has one proton)

Question 4

What is the radius of a nucelus (in metires)?

Answer 4

1 x 10^(-14) metres

(This is 1/10,000 of the size of the atom)

Question 5

What is the overall charge of the nucleus of an atom?

Answer 5

Positive

Question 6

In an atom, how does the numer of protons relate to the number of electrons?

Answer 6

They are the same - so there is no overall charge

Question 7

What happens when electrons are added or removed from an atom

Answer 7

The atom becomes positively (removed) or negatively (added) charged

This is called an “ion”

Question 8

What is the atomic number?

Answer 8

The number of protons in an atom

Question 9

What is the atomic mass (or mass number)?

Answer 9

The total number of protons and neutrons in an atom

Question 10

Where do you write the atomic number and mass number in a nuclear symbol?

Answer 10

Mass number: top left of the chemical symbol
Atomic number: botttom left of the chemical symbol

Question 11

How do you calculate the number of neutrons in an atom?

Answer 11

Subtract the atomic number (protons) from the mass number (protons + neutrons)

Question 12

Briefly describe the structure of an atom, using the terms proton, neutron, electron, nucleus and shell

Answer 12

Small central nucleus containing protons + neutrons
Orbiting electrons, that orbit around the nucleus in shells that are a fixed distance from the nucleus