1 Outline Chemical Elements Atoms Atomic Mass and Atomic Number Periodic Table Isotopes Electrons and Energy Molecules and Compounds Chemical Bonding Ionic and Covalent Hydrogen Properties of Water Acids and Bases

Learning Goals 1. You will be able to explain what matter is made of 2. You will be able to explain how the characteristics of an atom that makes it unique from other atoms 3. You will be able to answer why the properties of an atom affect its ability to bond with other atoms 2

3 Matter Matter is defined as anything that has mass and occupies space Matter exists in three states: solid, liquid, and gas All matter (both living and non-living) is composed of 92 naturally-occurring elements 98% of body weight of organisms are primarily composed of six elements (carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur— acronym CHNOPS)

4 Composition of Earth’s Crust versus Organisms FeCaKSPSiAlMgNaONCH Earth’s crust organisms Element Percent by Weight Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Gunter Ziesler/Peter Arnold, Inc.

5 Atomic Structure Atom is the smallest unit of an element Atoms composed of subatomic particles: Protons – positive charge weight of 1 AMU found in the nucleus Neutrons – no charge weight of 1 AMU similar to protons found in the nucleus Electrons – negative charge weigh 1/1836 th Dalton; found in electron shell

6 Subatomic Particles Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b.a. = proton = neutron = electron Particle Atomic Mass Unit (AMU) Location Electric Charge Subatomic Particles Proton Neutron Electron +1 0 – Nucleus Electron shell c.

Let’s Draw! Color in your copy of an atom and it’s corresponding parts Three hole punch and place in your Biology Binder 7

8 Atomic Symbols Each element is represented by one or two letters to give them a unique atomic symbol For Example: C = Carbon

Atomic Mass Each atom has its own specific mass (atomic mass) Atomic mass of an atom depends on the presence of subatomic particles Atomic number = # protons Atomic mass/mass number = # protons + neutrons 9

10 Atomic Symbol The atomic number is above the atomic symbol and the atomic mass is below the atomic symbol l

11 Periodic Table Elements grouped in periodic table based on characteristics Vertical columns = groups; chemically similar Horizontal rows = periods; larger and larger Atomic mass increases as you move down a group or across a period.

12 Periodic Table Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Periods Groups K Ca Ga Ge As Se Br Kr Na Mg Al Si P S Cl Ar Li Be B C N O F Ne I H atomic number atomic symbol He VIII atomic mass IIIIIIVVVIVII

13 Isotopes Isotopes: Atoms of the same element with a differing numbers of neutrons (and therefore have different atomic masses). e.g. see carbon below Some isotopes spontaneously decay Radioactive Give off energy in the form of rays and subatomic particles Can be used as tracers Mutagenic – Can cause cancer 12 6 Carbon 12 C 13 6 Carbon 13 C 14 6 Carbon 14 C

14 Some Medical Uses for Low Level Radiation MRI, CT, Nuclear Medicine a: © Biomed Commun./Custom Medical Stock Photo; b(Right): © Hank Morgan/Rainbow; b(Left): © Mazzlota et al./Photo Researchers, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b. a. larynx thyroid gland trachea

15 Some Medical Uses for High Level Radiation Radiation can kill cancer cell Radiation can preserve food longer Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: (Peaches): © Tony Freeman/PhotoEdit; b: © Geoff Tompkinson/SPL/Photo Researchers, Inc. a.b.