© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Chemistry Notes 6 th Grade Science

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements, Compounds, and Mixtures What Do You Think? How is an element different from a compound?

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Answer An element is made up of only one pure substance, and a compound is composed of two or more elements that are chemically combined. Gold Water

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements An element is a pure substance that cannot be separated into simpler substances by physical or chemical means.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements A pure substance is a substance in which every particle of that element is the same. –Example: Every particle in a 5g gold nugget is like every other particle of gold, no matter where they are found.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Every element has a unique set of properties. The Periodic Table of Elements is arranged according to these properties.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Every element has a unique set of properties. Some physical properties that are used to classify elements are boiling point, melting point, color, and density.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Chemical properties used to separate elements from each other include reactivity with acids, or reactivity with oxygen.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Are Grouped Some elements are shiny, and can conduct thermal energy. They are all grouped together on the left hand side of the Periodic Table. They are called metals. Not all metals are exactly alike, but they do have some properties in common.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Elements Can Be Identified By Categories If you know the category, you know the properties. Try this! 1. Share with your class how CDs can be classified by categories? 2. How can dogs be classified by categories?

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Elements are identified by 3 main categories Metals Nonmetals Metalloids

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Metals are elements that are usually shiny and good conductors of electricity and heat. Metals

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Metals are also malleable (can be hammered into thin sheets). Metals

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Metals are ductile, or can be drawn into thin wires. Metals are located to the left of the “zig zag line” on the Periodic Table.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Examples: Iron (Fe) and Copper (Cu).

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Click below to see properties of Metals.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Nonmetals Usually dull and poor conductors of heat and electric current. Tend to be brittle and unmalleable.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Nonmetals Nonmetals are located to the right of the “zig zag line” on the Periodic Table.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Nonmetals Examples: Neon (Ne) and Carbon (C) sign2.html reluctant-messenger.com/ diamond_sutra.htm

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Click below to see properties of Nonmetals

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Metalloids Share properties of both metals and nonmetals. Can be shiny or dull. Somewhat malleable and ductile.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Metalloids touch the “zig zag line” on the Periodic Table. Examples: Silicon (Si) Arsenic (As).

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements Click below to see properties of metalloids.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Let’s Review! Describe some physical properties of the element iron.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Answer Physical properties include: 1.Melting Point: 1535 °C 2.Density: 7.9 g/cm 3 3.Iron has the ability to conduct heat and electrical current.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Let’s Review What is an example of a metal that is very malleable, shiny, and is used often in kitchens?

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Answer Aluminum Foil

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Compounds What do salt, sugar, baking soda, and water have in common? What Do You Think?

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Compounds A compound is a pure substance composed of two or more elements that are chemically combined. Familiar Compound CompoundElements Combined Table SaltSodium and Chlorine WaterHydrogen and Oxygen SugarCarbon, Hydrogen, and Oxygen Carbon DioxideCarbon and Oxygen Baking SodaSodium, Hydrogen, Carbon, and Oxygen

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Compounds Properties of Compounds Compounds, like elements, can be identified by their own physical and chemical properties. What are some examples of physical and chemical properties?

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Compounds Each compound has different properties than the elements that make them up. WaterHydrogenOxygen Melting Point 0°C °C °C Boiling Point 100 °C °C °C Density 1.0 g/cm g/cm g/cm 3 State at Room Temperature LiquidGas

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Compounds Compounds are Composed of Elements. The compound Water is composed of Hydrogen and Oxygen chemically bonded together.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Compounds Compounds are Composed of Elements. The compound Ammonium is composed of Nitrogen and Hydrogen chemically bonded together.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Compounds Click below to see a video clip of sodium metal and chlorine gas being combined.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Let’s Review! What is the difference between an element and a compound?

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Answer An element is a pure substance that cannot be separated into simpler means by physical or chemical means. A compound is a pure substance composed of two or more elements that can be broken into simpler substances by a chemical change.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Compounds Make a Venn diagram comparing and contrasting elements and compounds. ElementsCompounds

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements, Compounds, and Mixtures Pre-AP Extensions for Chapter 2 Mixtures are combinations of two or more elements that are not chemically combined. Mixtures can be separated into 2 types: homogenous mixtures and heterogenous mixtures.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements, Compounds, and Mixtures Homogenous Mixtures A homogenous mixture is a mixture of two or more substances that is completely uniform in composition. Homogenous mixtures can be separated by physical means, but it is often difficult to do. Examples include salt water, kool aid, and air.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements, Compounds, and Mixtures Heterogenous Mixtures A heterogenous mixture consists of many different items, which are often not easily sorted or separated, though they are clearly distinct. Examples include oil and water mixed together, sand or gravel, and even chocolate chip cookies!

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Elements, Compounds, and Mixtures Websites to Visit Percent Calculations in a Mixture Chromatography Mixtures Lab

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table What Do You Think? How do scientists use physical properties to arrange elements on the periodic table?

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Dimitri Mendeleev discovered a pattern to the elements in the periodic table in quantique-histoire.htm

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table He simply wrote the names of all of the elements on cards, along with some of their properties.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Mendeleev tried arranging his cards based on different properties like color, density, melting point, and atomic mass. He found that by arranging the elements by increasing atomic mass, he found many other properties that fit a pattern.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Mendeleev found that by arranging the elements by increasing atomic mass, similar physical and chemical properties repeated in every 8 th element. This is called periodic, or having a regular, repeating pattern. Can you think of anything else that is periodic?

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Let’s Review! Why was Mendeleev so important in the study of the periodic table?

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Answer Mendeleev was responsible for arranging the periodic table by increasing atomic mass. This arrangement organizes the table making it easier for us to use.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table What Do You Think? How do scientists use physical properties to arrange elements on the periodic table?

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Elements are classified on the periodic table based on their properties. Like we learned in Chapter 2, we classify them as metals, nonmetals, and metalloids.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Remember that metals are shiny, ductile, malleable, and are good conductors of thermal energy and electrical current. Metals

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Metals are located to the left of the “zig zag” line on the periodic table. Metals

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Go.hrw.com Physical Properties of Metals

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Go.hrw.com Chemical Properties of Metals

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Remember also that nonmetals are not shiny and are poor conductors of thermal energy and electric current. Nonmetals

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Nonmetals are found to the right of the “zig zag” line on the periodic table. Nonmetals

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Go.hrw.com Physical and Chemical Properties of Nonmetals

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Metalloids are elements that have properties of both metals and nonmetals. Metalloids

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Metalloids border the “zig zag” line on the periodic table. Metalloids

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Go.hrw.com Physical and Chemical Properties of Metalloids

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Let’s Review! Use the properties of metalloids to explain their position on the periodic table.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Answer Metalloids are located between metals and nonmetals because they have properties in between metal and nonmetals.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Pre-AP Extensions for Chapter 3 There are trends in Metallic and Nonmetallic Character that we can see on the periodic table. Metallic character is strongest for the elements in the leftmost part of the periodic table, and tends to decrease as we move to the right in any period.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Within any group of elements (columns), the metallic character increases from top to bottom. This general trend is not necessarily observed with the transition metals.

© Fall 2005, Pflugerville ISD, 7th GradeUnit 1 Introduction to the Periodic Table Pre-AP Extensions for Chapter 3