BIL 150 Chapter Notes - Chapter 2: Radionuclide, Unified Atomic Mass Unit, Mass Number
28 Apr 2016
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Matter= anything that takes up space and has mass. Element cannot be broken down to other substances: 92 elements. Compound is two or more elements combined in a fixed ratio. O, c, h, n make up 96% matter. Trace elements are required by animals in tiny quantities. Subatomic particles so small instead of grams we use the dalton (same as amu) Isotope different number neutrons: radioactive isotope has nucleus decaying spontaneously giving off particles and energy. Used as tracers to see results in pet scans. Two or more atoms held together by covalent bonds = molecule. Transfer of an e- is not the formation of a bond: it allows a bond to form because it results in 2 ions of opposite charge. Ionic compounds formed by ionic bonds are also known as salts. Hydrogen bond s the attraction between a hydrogen and an electronegative atom.
