BSC 114 Lecture Notes - Lecture 1: Van Der Waals Force, Covalent Bond, Valence Electron
7 Apr 2016
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Bsc 114 lecture 1- the chemical context of life. Matter- anything that takes up space and has mass. Element- matter that cannot be broken down to other substances by chemical reactions. An element"s chemical properties depend on the structure of its atoms. Atom- smallest unit of matter that still retains the properties of an element. A compound is a substance consisting of two or more elements in a fixed ratio. A compound has characteristics different from those of its elements. About 20-25% of the 92 elements are essential to life. Oxygen, carbon, hydrogen & nitrogen comprise about 96% of human body mass. Trace elements are required by an organism in minute quantities. Proton mass and neutron mass are almost identical and measured in units called daltons (1 da = about the mass of 1 proton) Protons & neutrons- 1. 67 x 10-24 grams each. About one millionth of a billionth of a billionth of a gram.
