L2 Atom structure & Isotopes Flashcards
What is a proteon?
The protons & neutrons
What is the atomic number?
No. of protons in the nucleus of an atom - allows the element to be identified.
What is the mass number?
Sum of the protons & neutrons in the nucleus
What is an orbital?
The specific region around the nucleus that e- occupy.
What is a shell?
Families that orbitals are grouped into - can be identified by the principal quantum no.)
What are isotopes?
= atoms with the same atomic no. but different mass no. = same no. of protons & different no. of neutrons.
- Chemically identical because they have the same outer e- & chemical identity
- Physical properties can differ
What is the kinetic isotope effect?
= heavier isotopes react slightly more slowly
What are the hydrogen isotopes?
- what are they used for?
H-1 = Protium - most abundant isotope H-2 = Deuterium - used in isotopic labelling experiments, very useful in NMR, safe substance H-3 = Tritium - radioactive, used in labelling experiments
What are the carbon isotopes?
- what are they used for?
C-12 - most abundant isotope
C-13 - useful in NMR
C-14 - used in radiocarbon dating as C-14 is accumulated in living tissue (stops once the sample is dead), C-14 decays at a steady rate so the quantity of it in a sample can be used to estimate age - forensic/archaeology
What are stable isotopes?
= Isotopes that remain unchanged indefinitely
What are unstable isotopes?
= Isotopes that undergo spontaneous decay in order to become a stable nucleus (this results in the emission of small particles/radiation)
= Radioactive isotopes
What is mass spectrometry?
= An analytical technique that measures the Mr of atoms/compounds by observing the mass to charge ration (m/z) of ions (the ions are separated on the basis of their masses & motions in magnetic or electrical fields)
- Works for both stable/unstable isotopes
- Applications: determining isotopic abundances, identify small molecules/atoms, biomarkers of disease, identifying if you have the desired/predicted product
What are the uses for stable isotopes: Calcium-42, -44, -46 & -48?
- Ca metabolism, bioavailability & absorption parameters during physical stress, bed rest & space flight
- Osteoporosis research & bone turnover studies
- Role of nutritional Ca in pregnancy, growth & development & lactation
- Bone changes associated with diseases such as diabetes and cystic fibrosis
What are the uses for Carbon-13?
- Elucidation of metabolic & bio synthetic pathways
- Noninvasive breath tests for research and diagnosis
- Molecular fingerprinting- dope testing athletes
What are the uses for Copper-63, -65?
Noninvasive studies of copper metabolism and requirements.
What are the uses for Helium-3?
In vivo magnetic resonance studies
What are the uses for Hydrogen-2?
- Vitamin research
- Chemical reaction mechanisms
What are the uses for Iron-54, -57, -58?
- Metabolism, energy expenditure studies
- Research to develop successful intervention for anaemia
- Metabolic tracer studies to identify genetic iron control mechanisms
What are the uses for Krypton-78, -80, -82, -84, -86?
Diagnosis of pulmonary disease.
What are the uses for Lithium-6?
- Na & renal physiology
- Membrane transport
- Psychiatric diseases
What are the uses for Nitrogen-15?
- Whole body protein turnover, synthesis & catabolism
- Amino acid pool size & turnover
- Metabolism of tissue and individual proteins
What are the uses for Oxygen-18?
- Studies of metabolism & energy expenditure
- Lean body mass measurements
- Obesity research
What is radioactive decay?
The nucleus of an unstable radioisotope seeks energetic stability by emitting particle/radiation: alpha, bet and gamma protons
What is half-life (t1/2)?
= the time taken for the activity of a given amount of a radioactive substance to decay to half of its initial value.
