BIOL 105 Lecture Notes - Atomic Nucleus, Atomic Number, Emergence
Document Summary
Matter consists of chemical elements in pure form and in combinations called. An element"s properties depend on the structure of its atoms. The formation and function of molecules and ionic compounds depend on chemical bonding between atoms. Chemical reactions make and break chemical bonds. Matter - anything that takes up space and has mass. Element - substance that cannot be broken down by chemical means. Compound - substance of two or more elements in fixed ratio. Compound characteristics (emergent properties) different than constituent elements. Properties of compounds depend on atoms and how they are bonded. Essential elements - 20-25% of the 92 natural elements are necessary for life. Carbon, hydrogen, oxygen, and nitrogen make up 96% of living matter. Most of the remaining 4% include calcium, phosphorus, potassium, and sulfur. Trace elements - required by organisms in minute quantities. Atom - smallest unit of matter that still retains properties of an element.
