CAS BI 107 Chapter Notes - Chapter 2: Ionic Bonding, Hydrogen Bond, Atomic Number
Document Summary
Chapter 2: the chemical context of life 4/16/2015 9:29:00 pm. Concept 2. 1 matter consists of chemical elements in pure form and in combinations called compounds. Oxygen, carbon, hydrogen, and nitrogen makes up 96% of living matters. Calcium, phosphorus, potassium, sulfur, and a few other elements are the 4% Trace elements needed in only minute quantities (i. e. iron) Some natural elements are toxic, like arsenic for humans (can be found in water: some organisms adapt to the toxic elements in its environments. Concept 2. 2 an element"s properties depend on the structure of its atoms. Atom smallest unit of matter, retaining properties of elements. Energy capacity to cause change (do work) Electrons have different potential energy: farther it is from the nucleus, higher the energy. Electrons are found in different electron shells of different distance: when an electron absorbs energy, it moves to a farther shell, when it loses energy, it falls to a closer shell, releasing energy as heat.
