BIOL 101 Chapter Notes -Chemical Equilibrium, Unified Atomic Mass Unit, Atomic Mass
Document Summary
Element of life: essential elements: consists of about 20-25% of the 92 natural elements. Iodine deficiency disease called goiter: atom: smallest unit having properties of an element and are composed of. Atomic number and atomic mass: atomic number: total number of protons. Written as subscript to the left of the element symbol. Tells us the number of protons and the number of electrons in a electrically neutral atom: mass number: sum of protons and neutrons in nucleus. Radioactive tracers: used in medicine to track atoms during metabolism, ex. Some kidney disorders are diagnosed by injecting small doses of radioactively labeled substances into blood and analyzing the tracer molecules excreted in the urine. Electron distribution and chemical properties: chemical behavior of an atom depends on the number of outer electrons (valence electrons) and the outermost shell (valence shell, full valence shell = inert. Covalent bonds: cation: positively charged, anion: negatively charged, applies to entire molecules that are electrically charged like nh4.
