Struture 1.2 The Nuclear Atom Flashcards
What is the mass number of an atom?
Mass Number = number of protons and neutrons in the nucleus
What is the atomic number of an atom?
Atomic Number = number of protons in nucleus, unique to each element
Are all atoms of the same element identical?
No, they can have different isotopes
What is the definition of an isotope?
Isotopes are atoms of the same element with the same number of protons but different number of neutrons
How do isotopes of an element differ?
They differ in their nucleon numbers
What are the two isotopes of chlorine mentioned?
- Chlorine-35 (75%)
- Chlorine-37 (25%)
Do isotopes have the same chemical properties?
Yes, but they differ slightly in their physical properties
What are radioisotopes?
Isotopes that emit high energy radiation
What is the use of Cobalt-60?
Used to treat cancer patients (radiotherapy)
What is the atomic mass symbol?
Symbol: m_a
What does atomic mass include?
The masses of protons, neutrons, and electrons
Why is it impractical to use actual atomic masses in calculations?
Atoms are too small and light
What is the relative atomic mass (Ar)?
The weighted mean mass of all the naturally occurring isotopes of an element relative to 1/12th the mass of a carbon-12 atom
Why are relative atomic masses not whole numbers?
Due to the existence of isotopes of different masses with different isotopic abundances
How is the relative atomic mass of chlorine calculated?
A_r of Cl = ((75 x 34.97) + (25 x 36.97)) / 100 = 35.45
What is mass spectrometry?
A process to determine the atomic mass of atoms or molecules
What does mass spectrometry measure?
Mass-to-charge ratios (m/z or m/e) for particles
What data is obtained from mass spectrometry?
A graph plotting mass per charge against relative abundance
What are the stages of mass spectrometry?
- Vaporisation
- Ionisation
- Acceleration
- Deflection
- Detection
What happens during the ionisation stage?
Gaseous atoms are hit with high-energy electrons to produce positively charged ions
What is detected in the detection stage?
Positively charged ions and their abundance
What isotopes does Boron exist in?
- 10B
- 11B
How many stable isotopes does Chromium have?
4 stable isotopes
