2.1.1 - Atomic Structure And Isotopes

Question 1

What is an isotope?

Answer 1

An atom of the same element but with a different number of neutrons and different masses

Question 2

What is an Ion?

Answer 2

A charged atom
Cations are pos
Anions are neg

Question 3

What is relative isotopic mass?

Answer 3

The mass of an isotope relative to a 1/12 of the mass of an atom of carbon 12

Question 4

What is relative atomic mass?

Answer 4

The weighted mean mass of an atom of an element relative to 1/12th of the mass of an atom of carbon 12

Question 5

What does a mass spectrometer do?

Answer 5

It finds the % abundances of the isotopes in a sample of an element

Question 6

How does a mass spectrometer work?

Answer 6

1. A sample is placed in the mass spectrometer
2. The sample is vaporized and ionized to form positive ions
3. The ions are accelerated. Heavier ions move more slowly and are more difficult to deflect
4. Ions are detected on a mass spectrum as a mass-to charge ratio
   - greater the abundance, greater the signal

Question 7

Uses of mass spectrometry

Answer 7

Forensic science

• detecting illegal drugs
• Space exploration
• carbon14 dating

Question 8

Why is carbon 12 the standard?

Answer 8

• it is solid in a room (unlike 02)
• it is easy to get
• has existed as many kinds of materials
• existence of other isotopes are too little