Biology 9

Biology 9 - Biology 8/27 Chapter 2 Atoms A (with out), toms...

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Chapter 2 Atoms A (with out), toms (break apart) Bohr model: Protons-positive charge, weight of 1 Neutrons- no charge, weight of 1 Electron- negative charge, no weight Weak force= attraction b/n protons and electrons Strong force=keeps protons and electrons together Atomic mass unit (amu) or Dalton 1 proton and 1 neutron have a mass of about 1 dalton 1.7 x 10^-24 earths crust=half oxygen, 28% silicon, 8% aluminum, and 2-5% of sodium, magnesium, potassium, calcium, and iron about 98% f the mass of every living organism is composed of just six elements: carbon, hydrogen, nitrogen, oxygen, phospherus, and sulfer. (CHONPS) Ca- act as a biological signal Iodine-component of vital hormone atom Magnesium and molybdenum are essential to plants Atomic #= # of protons Mass #- total # of protons and neutrons number of protons plus number of neutrons averaged over all isotopes Isotopes=number of protons but differ in neutrons Radioisotopes-unstable and spontaneously give off energy in the form of alpha, beta, or gamma radiation from the atomic nucleus. Radioactive decay-release of energy transforms the original atom. These transformations can extend even to a change in the number of protons, so that the original atom is now a different element. The energy released by radioactive decay can interact with surrounding substances. 1
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Biology 9 - Biology 8/27 Chapter 2 Atoms A (with out), toms...

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