Paper 1 - Atomic Structure

Question 1

What is relative atomic mass (Ar)?

Answer 1

an average value that takes account of the abundance of the isotopes of the element

Question 2

What is an isotope?

Answer 2

Isotopes have - the same atomic mass
- but different atomic number

Question 3

What is atomic number?

Answer 3

The number of protons in the nucleus

Question 4

Describe the structure of an atom

Answer 4

• Nucleus in the centre containing protons and neutrons + has an overall neutral charge
• Shells of electrons surrounding the nucleus
• Electron mass = 1/2000
• Proton/Neutron mass = 1
• There are equal numbers of protons and electrons so the atom has an overall neutral charge

Question 5

Define a molecule

Answer 5

• A group of 2 or more atoms chemically bonded together
• Smallest unit of a compound that retains its chemical properties

Question 6

What is mass number?

Answer 6

The sum of protons and neutrons in a nucleus