1 Chapter 3Atoms and Elements 3.1 Classification of Matter Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

2 Learning Goals Classify matter as pure substances or mixtures. Given the name of an element, write its correct symbol; from the symbol, write the correct name. Use the periodic table to identify the group and the period of an element and decide whether it is a metal, nonmetal, or metalloid. Describe the electrical charge and location in an atom for a proton, a neutron, and an electron. Given the atomic number and the mass number of an atom, state the number of protons, neutrons, and electrons. Give the number of protons, electrons, and neutrons in the isotopes of an element. Given the name or symbol of one of the first 18 elements in the periodic table, write the electron arrangement and use it to explain the periodic law. Use the electron arrangement of elements to explain periodic trends.

3 Matter Matter is the “stuff” that makes up all things. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

4 A pure substance is classified as matter with a specific composition. an element when composed of one type of atom. a compound when composed of two or more elements combined in a definite ratio. Pure Substances

5 Elements Elements are pure substances that contains atoms of only one type. Copper, Cu Lead, Pb Aluminum, Al Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

6 Compounds contain two or more elements in a definite ratio. Salt (NaCl) Table sugar (C 12 H 22 O 11 ) Water (H 2 O) Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

7 Elements in a Compound “Table salt” is a compound that contains the elements sodium and chlorine. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

8 Mixtures A mixture is a type of matter that consists of two or more substances that are physically mixed, not chemically combined. two or more substances in different proportions. substances that can be separated by physical methods.

9 Physical Separation of A Mixture Example: Pasta and water are separated with a strainer.

10 Homogeneous Mixtures In a homogeneous mixture, the composition is uniform throughout. the different parts of the mixture are not visible. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

11 Heterogeneous Mixtures In a heterogeneous mixture, the composition of substances is not uniform. the composition varies from one part of the mixture to another. the different parts of the mixture are visible. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

12 Classification of Matter

13 Identify each of the following as a pure substance or a mixture. A. pasta and tomato sauce B. aluminum foil C. helium D. air Learning Check

14 Identify each of the following as a pure substance or a mixture. A. pasta and tomato saucemixture B. aluminum foilpure substance C. helium pure substance D. air mixture Solution

15 Identify each of the following as a homogeneous or heterogeneous mixture: A. hot fudge sundae B. shampoo C. sugar water D. peach pie Learning Check

16 Identify each of the following as a homogeneous or heterogeneous mixture: A. hot fudge sundaeheterogeneous mixture B. shampoo homogeneous mixture C. sugar water homogeneous mixture D. peach pie heterogeneous mixture Solution