Topic One: Atomic Structure

Question 1

Describe atom structure

Answer 1

Nucleus with protons and neutrons, surrounded by electrons in shells

Question 2

Describe​ ​how​ ​the​ ​Dalton​ ​model​ ​of​ ​an​ ​atom​ ​has​ ​changed​ ​over​ ​time

Answer 2

Mention Rutherford’s gold foil alpha particle experiment if this comes up

Question 3

Recall​ ​the​ ​relative​ ​charge​ ​and​ ​relative​ ​mass​ ​of​ ​protons,​ ​neutrons​ ​and
electrons

Answer 3

Proton:
Charge = +1
Mass =1

Neutron:
Charge = 0
Mass = 1

Electron:
Charge = -1
Mass = 1/1836

Question 4

Explain​ ​why​ ​atoms​ ​contain​ ​equal​ ​number​ ​of​ ​protons​ ​and​ ​electrons

Answer 4

• Protons have a +1 charge and electrons have a -1 charge
• Atoms are neutral
• Neutrons have no charge
• So, there must be the same number of protons and electrons so that the atom is neutral

Question 5

Where is most of the mass of an atom concentrated?

Answer 5

The nucleus
(the nucleus is also vey small compared to the size of the atom)

Question 6

What does the mass number mean?

Answer 6

Number of protons + neutrons

Question 7

What are isotopes?

Answer 7

​ different​ ​atoms​ ​of​ ​the​ ​same​ ​element​ ​containing
the​ ​same​ ​number​ ​of​ ​protons​ ​but​ ​different​ ​numbers​ ​of​ ​neutrons​ ​in
their​ ​nuclei

Question 8

Formula for: the​ ​ relative​ ​ atomic​ ​ mass​ ​ of​ ​ an​ ​ element​ ​ from
the​ ​ relative​ ​ masses​ ​ and​ ​ abundances​ ​ of​ ​ its​ ​ isotopes

Answer 8

​ ​​
(mass of isotope-A x % of isotope-A) + (mass of isotope-B x % of isotope-B)
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100