C1.2- Atomic Structure

Question 1

What are atoms?

Answer 1

• the smallest particle of an element that’s still has its chemical properties

Question 2

What’s a molecule?

Answer 2

• made from two or more atoms joined together
• joined by attractive forces (chemical bonds)
• the atoms within can all be the same or they can be different

Question 3

What’s inside an atom?

Answer 3

• the inside’s mostly empty space
• contains three subatomic particles
• protons(+1)and neutrons(0)joined together as the nucleus at the centre
• electrons(-1)surrounding the nucleus in shells

Question 4

What are isotopes?

Answer 4

• atoms with the same number of protons and electrons but different numbers of neutrons
• same atomic number but their mass number’s different

Question 5

What did John Dalton do?

Answer 5

• suggested all matter is made from atoms

- atoms were tiny solid balls

Question 6

What did Thomson do?

Answer 6

• discovered the electron
• cathode rays were tiny particles that were negatively charged, smaller than atoms
• in his plum pudding model he suggested that atoms were spheres of positive charge with electrons dotted around inside

Question 7

What did Ernest Rutherford do?

Answer 7

• pointed beams of positively charged alpha particles at thin gold foil
• most went straight through
• but many changed direction slightly
• some even came straight back
• an atom has a positively charged nucleus containing most of its mass
• outside the nucleus electrons orbit like planets

Question 8

What did Bohr do?

Answer 8

• orbiting electrons would be attracted to the oppositely charged nucleus and would rapidly spin inwards
• he showed that electrons occupy fixed energy shells/levels around the nucleus