Section 1: The Nature of Matter Chapter 2 Section 1: The Nature of Matter
Objectives Identify the three subatomic particles. Explain how all of the isotopes of an element are similar and how they are different. Explain what chemical compounds are. Describe the two main types of chemical bonds.
Life Depends on Chemistry Everyday, materials are used in chemical reactions that take place in your body to keep you alive.
Atoms Basic units of matter Contain subatomic particles Protons: + charge Neutrons: no charge Electrons: - charge *Neutrons and protons form the nucleus
Nucleus Located at the center of the atom Formed by strong forces that bind protons and neutrons together.
Electrons http://www.teachersdomain.org/asset/phy03_vid_atoms/ Negatively charged particles 1/1840 the mass of a proton In constant motion in the space surrounding the nucleus
Atoms are Neutral Equal number of protons and electrons
Elements Element: pure substance that consists entirely of one type of atom. Represented in one or 2-letter symbols. Atomic Number: represents # of protons
Isotopes Atoms of the same element that differ in the number of neutrons they contain. Have the same chemical properties as the element because they have = electrons. Identified by their mass number: sum of protons and neutrons in the nucleus.
Radioactive Isotopes http://www. pbs Have unstable nuclei Break down at a constant rate over time Used to determine age of rocks, treat cancer and kill bacteria.
Chemical Compounds Substances formed by the chemical combination of two or more elements in definite proportions. Identified by chemical formulas: ex. H2O
Chemical Bonds Hold atoms together Formed by valence electrons (electrons on outer shell) Two Types Ionic Covalent
Ionic One or more electrons are transferred from one atom to another. The atom that gains or loses electrons are called IONS.
Covalent Electrons are shared between atoms. MOLECULES are formed when atoms form covalent bonds.
Molecules Smallest unit of most compounds.
Van der Waals Forces Slight attraction that develops between oppositely charged regions of nearby molecules. Geckos use theses forces to climb vertically.
Section 2-1 Questions Describe and draw the structure of an atom. Why do all isotopes of an element have the same chemical properties? In what way do isotopes of an atom differ? What is a covalent bond? An ionic bond? What is a compound?
Video Clip http://www.unitedstreaming.com/search/assetDetail.cfm?guidAssetID=C8F42D6F-EB08-4597-A596-43C9B539BE16 http://www.quia.com/shared/chem/