BSC 2010C Chapter 2: BSC 2010C Chapter 2
Document Summary
Chemical elements in pure form: matter: anything that takes up space and has mass. Element: substance that cannot be broken down to other substances by chemical reaction. Compound: substance consisting of two or more di erent elements combined in a xed ratio. Essential elements: organism needs to live a healthy life and reproduce four elements hydrogen oxygen nitrogen carbon make up 96% of living matter. Atom: smallest unit of matter that retains properties of an element: atomic nucleus: dense core at the center of the atom, neutron: electrical neutral. Electron cloud: space around the nucleus that contains electrons. Electron: electrically charged (-: measured in daltons; amu (atomic mass unit) Atomic number: the number of protons in a speci c element also provides number of electrons to maintain stability: mass number: way to nd the amount of neutrons sum of protons plus neutrons in the nucleus.
