BIOL 102 Lecture Notes - Lecture 2: Electron Shell, Atomic Number, Unified Atomic Mass Unit
Document Summary
Evaluate if evaluations show you prediction are incorrect, then revise hypothesis; if correct, then repeat experiment and verify if unsuccessful, repeat; if successful, ask a new question. 25 of the 92 elements are essential to life. 4 of these elements make up 96% of living matter (chon) Carbon (18. 5%), oxygen (65%), hydrogen (9. 5%), nitrogen (3. 3%) Nitrogen helps to build amino acids for proteins nitrogen is a big limiting factor in the environment. Most of the remaining 4% essential to life elements consists of calcium, phosphorus, potassium and sulfur. Properties of atoms depend on structure composed of 3 subatomic particles. Protons and neutrons are in the nucleus of an atom while electrons form negative cloud and determine chemical behavior outside the nucleus. Protons are the identity of the atom atomic number = # of protons. Electrons determine how the atom will react with another atom. Atomic mass = # of protons + # of neutrons.
