Biochemical Aspect of Biology L. Jones

8 Characteristics of Living Things All living things are made of 1 or more cells. All living things have a way to reproduce. All living things grow and develop. All living things share a universal genetic code (Have DNA and RNA) All living things must obtain material and use the energy from them. All living things maintain a fairly stable internal environment. All living things are able to respond to environmental changes. As a group, living things change over time(evolve)

Atoms Atoms are the basic unit of matter. They are made up of 3 subatomic particles Protons Have a positive charge Found in the nucleus Neutrons Have no charge/neutral Electrons Have a negative charge Found in a orbital/cloud surrounding the nucleus

Picture of an Atom

Things to Know

Elements element name

Isotopes Isotopes are the same element, but may have different properties because of their different masses that may change its stability. Isotopes are named by adding the number of protons and neutrons. Some isotopes are useful in telling the age of fossil

Bonding valence An atom’s valence electrons are those electrons that have the highest energy level and are held most loosely. The number of valence electrons in an atom of an element determines properties of that element, including how well the atom bonds with other atoms. In order for an element to be stable it must have 8 electrons in its outer shell. This is the Octet Rule.

Electron Dot Diagram Electron dot diagrams show the symbol for the element surrounded by dots. Each dot stands for one valence electron

Types of Bonds Ionic bonds are the attraction between two oppositely charged ions. Electrons are transferred between elements to form the bond. Ions that are made of more than one atom are called polyatomic ions. When an atom gains an electron, it gains a negative charge and becomes a negative ion. When an atom loses an electron, it loses a negative charge and becomes a positive ion. An Ion is an atom or group of atoms that has an electric charge.

Covalent bond A covalent bond is a chemical bond that is formed when two atoms share electrons. A molecule is a neutral group of atoms joined by covalent bonds and usually make up living tissues.

How can you tell if it is ionic or covalent? An ionic bond occurs between a metal and a non-metal. A covalent bond occurs between two non-metals. Unless you memorized the periodic table, you're going to need a periodic table.