Elements, Compounds, and Mixtures

1. Elements, Compounds, and Mixtures What Do You Think? How is an element different from a compound?

2. 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 http://www.worldofrockhounds.com/huge-gold-nugget-sm.JPG Water http://www.nbmg.unr.edu/slides/water/5.htm

3. Elements An element is a pure substance that cannot be separated into simpler substances by physical or chemical means.

4. Elements Every element has a unique set of properties. The Periodic Table of Elements is arranged according to these properties.

5. 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.

6. Elements Chemical properties used to separate elements from each other include reactivity with acids, or reactivity with oxygen.

7. 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.

8. Elements Elements Can Be Identified By Categories If you know the category, you know the properties. 1. Share with your class how CDs can be classified by categories? 2. How can dogs be classified by categories? Try this!

9. Elements are identified by 3 main categories Metals Nonmetals Metalloids Elements

10. Elements Metals Metals are elements that are usually shiny and good conductors of electricity and heat.

11. Elements Metals Metals are also malleable (can be hammered into thin sheets).

12. 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

13. Elements • Examples: Iron (Fe) and Copper (Cu). http://www.flamo.net/crystals/iron.jpg http://resourcescommittee.house.gov/subcommittees/emr/usgsweb/materials/copper.html

14. Elements Nonmetals • Usually dull and poor conductors of heat and electric current • Tend to be brittle and unmalleable • Mostly gases

15. Elements Nonmetals • Examples: Neon (Ne) and Carbon (C) www.neonstreet.com/ sign2.html reluctant-messenger.com/ diamond_sutra.htm

16. Elements Metalloids • Share properties of both metals and nonmetals • Can be shiny or dull • Somewhat malleable and ductile • Semiconductor

17. Elements • Metalloids touch the “zig zag line” on the Periodic Table • Examples: Silicon (Si) Arsenic (As).

18. Let’s Review! - 1 - Describe some physical properties of the element iron. http://neil.fraser.name/news/2004/05/22/

19. Answer Physical properties include: • Melting Point: 1535 °C • Density: 7.9 g/cm3 • Iron has the ability to conduct heat and electrical current

20. Let’s Review - 2 - What is an example of a metal that is very malleable, shiny, and is used often in kitchens?

21. Answer Aluminum Foil

22. Compounds What Do You Think? What do salt, sugar, baking soda, and water have in common?

23. Compounds A compound is a pure substance composed of two or more elements that are chemically combined.

24. 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?

25. Compounds Each compound has differentproperties than the elements that make them up.

26. Compounds Compounds are Composed of Elements. The compound Water is composed of Hydrogen and Oxygen chemically bonded together.

27. Compounds Compounds are Composed of Elements. • The compound Ammonium is composed of Nitrogen and Hydrogen chemically bonded together

28. Let’s Review! - 1 - What is the difference between an element and a compound?

29. 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