BIOL 1010U Lecture Notes - Lecture 1: Valence Electron
5 May 2016
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Document Summary
In ancient greece aristotle addressed earth, air, fire and air as elements all matter composed of some of these elements. Elements were defined as substances that cannot be broken down. Elements = made up of one type of atom. Contains dense section in the middle called the nucleus. Made up of particles called protons and neutrons neutrons are electrical neutral, protons are positive. Electrons orbit the nucleus to balance out the positive charge in the middle. Neutrons can differ between atoms of the same element = isotopes. Isotope use in everyday life: agriculture- phosphorous-32 is used to study phosphorous usage in plants. Gamma rays from cobalt-60 kill bacteria on foodstuffs. Carbon-14 dating can show how long an organism has been dead. One orbital can only be used by two electrons at any time. Closer to nucleus = less energy so they fill up orbitals closer to the nucleus first. All orbitals in one energy level make up a shell.
