“…beneath the clothes, we find a man... and beneath the man we find... his... nucleus.”-Nacho Libre Reference Text - Modern Biology Chapter 2 / pgs

 All organisms are made of matter.  The structure and function of all living things are governed by the laws of chemistry.  Matter is constantly being rearranged through chemical reactions.  Chemical structures and reactions are central to all biological processes.

What do living and non-living have in common? All things are made up of matter.  Matter-anything that takes up space and has mass (solids, liquids, gas, plasma). ◦ Mass – the amount matter an object has. Chemical Changes in matter are essential to ALL life processes.

ATOMS ! Matter is made of tiny little particles called ATOMS ! You cannot see atoms because they are so small. Lots of atoms join together to make up matter that you can see.

Nucleus Nucleus - central core of the atom, consisting of: ◦ Protons ◦ Protons (+ charge) ◦ N eutrons ◦ N eutrons (neutral or no charge).  Electrons  Electrons (- charge) are found moving very fast around the nucleus in orbitals (electron cloud/energy levels).  Atoms with no charge (neutral) have equal protons and electrons. Protons Neutrons Electrons

Properties of atoms determine the structure and properties of the matter they compose.

Protons (in nucleus) Neutrons (in nucleus) Electrons Charge Positive (+) Neutral (no charge) NEGATIVE (-) MassBig VERY small

DRAW A PICTURE OF AN ATOM (LABEL ALL THE PARTS)

Atoms Atoms can join together in different ways to make different kinds of matter. atom. Some matter has only one kind of atom. ELEMENT. This is called an ELEMENT.

element An element is:  A pure substance that cannot be broken down chemically into simpler kinds of matter.

THE PERIODIC TABLE. Elements are arranged on THE PERIODIC TABLE. The table provides information such as chemical symbol, atomic number and atomic mass for each element.

Atomic Number protons (also tells the # of electrons) Atomic Number - # of protons in an atom (also tells the # of electrons). Atomic Mass # Atomic Mass # - number of protons + number of NEUTRONS FYI - if you are talking about average atomic mass, which is shown on the periodic table, it is the sum of the masses of the common isotopes of an element. How to Read the “Periodic Table” elementsymbol Each element has unique chemical symbol

There are more than 100 elements, but only about 30 are important to living things: 6 Major elements:  Carbon – 18.5%  Hydrogen – 9.5%  Oxygen – 65%  Nitrogen – 3.3% ◦ Phosphorus – 1.0% ◦ Sulfur – 0.3%  Others - K, Ca, Na, Fe (trace elements) Approximately 95% of the mass of living things is made up of these four elements

Under normal conditions, most elements do not exist by themselves… compound CO 2, H 2 O 2, H 2 O  A compound is a pure substance made up of atoms of 2 or more elements chemically joined, making them more stable Examples: CO 2, H 2 O 2, H 2 O  A molecule is the simplest part of a substance - 2 or more atoms chemically joined together. : H 2 O, O 2, CO 2, Examples: H 2 O, O 2, CO 2, H 2 O 2, H 2 H 2 O 2, H 2

1. Share electrons2. Steal electrons Covalent Bond Ionic Bond Sa lt- the outer electron of Na atom is transferred to the Cl atom ~this results in ions - an atom with a + or – charge. Because + and – attract, this attraction is called an ionic bond.

Atom of OxygenMolecules of OxygenCompound containing Oxygen