Atomic structure by Ruth
- Created by: Ruth
- Created on: 20-04-13 13:37
The atom and atomic structure
Nuclide: atom with specific number of protons and neutrons
Three subatomic particles: neutrons, protons and electrons
Neutrons + Protons contained in nucleus NOT electrons
Two regions in atom: nucleus + electron shells
Relative mass/Relative charge for
protons: 1/ +1
neutrons: 1/ 0
electrons: 5 x 10E-4/ -1
Atomic number: number of protons in the nucleus
Mass number: total number of protons and neutrons
Number of neutrons = mass number - atomic number
Isotopes: Atoms of the same element with different mass numbers: different numbers of neutrons
e.g. carbon-12, carbon-13
Isotopes of same chemical element: identical chemical properties + different physical properties
Unstable nuclides: emission of ionizing radiation: radioactive - radioisotopes
Types of radiation: Deflection by electric field
Alpha: low
Beta: high
Gamma: none
During alpha + beta radioactive decay: formation of more stable isotope
Uses of radioisotopes:
In medicine:
Iodine -131: used to treat thyroid cancer
Iodine-125: treat prostate cancer + brain tumors
Cobalt-60: very powerful gamma emitter + suppress body's immune reaction to organ transplantations
Radiotherapy: damaging DNA of cancer cells
In archeology:
Carbon-14: radiocarbon dating: used to date organic remains accurately for up to 100 000 years
Positive ions: formed when…
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