Atomic Structure

Question 1

Where are electrons located?

Answer 1

• electrons surround the nucleus in specific regions called orbitals. A completely filled shell is very stable (noble gases)

Question 2

What is an Isotope?

Answer 2

Atoms with the same atomic number but different mass number (or the same number of protons but different number of neutrons)

Question 3

What’s the main difference between stable and unstable isotopes?

Answer 3

stable isotopes: remain unchanged indefinitely
unstable isotopes: undergo disintegration to become a stable nucleus. disintegration causes radiation (Radioactive isotopes)

Question 4

What is mass spectrometry?

Answer 4

Measures the molecular weight of atoms or compounds observing the mass to charge ratio of ions

Question 5

During radioactive decay what particles/ radiation are emitted

Answer 5

• Alpha
• Beta
• Gamma photons

Question 6

Define half-life t1/2

Answer 6

The time taken for the activity of a given amount of a radioactive substance to decay to half of its initial value

Question 7

What is Alpha radiation?

Answer 7

• emission of an alpha particle
• helium nuclei
• positively charged

Question 8

What are gamma rays?

Answer 8

• emission of a gamma photon
• high frequency EM radiation
• neutral
• no effect on atomic or mass number

Question 9

What is beta radiation?

Answer 9

• Two types
• beta minus = emission of an electron
• beta plus = emission of a positron (anti-electron)

Question 10

What are the applications or unstable isotopes?

Answer 10

• Industrial e.g energy generation
• Domestic e.g smoke detectors
• Medical - e.g diagnostic