1.Introduction . 2 What is matter? 1.The structure of matter- Any object or substance that has mass and takes up space. 2. 3. What are atoms? 3. Atoms are tiny particles that make up all matter AND the smallest particle of an element. 4. Describe the nucleus. 4. The nucleus is at the center of the atom. The nucleus contains neutrons and protons. The nucleus spins. Interesting fact: the smallest nucleus is located in a light hydrogen atom; the largest- uranium. What are protons? 5. Protons have a positive electric charge, have a mass of 1, and how many protons determine the element. 6. What are neutrons? 6. Neutrons have no electric charge and have a mass of 1; located in the nucleus. 5. What are electrons? 7. Electrons have a negative electric charge; have a mass of almost 0; electrons fly around the nucleus almost at the speed of light when in orbit. 7. Let’s Review What are 8. Ions are atoms with an extra or missing ions? 8. electron. When ions have a ( an): •extra electron, the charge is negative •A missing electron , the charge is positive -----------------------------------------Remember that normal atoms have the same number of electrons and protons 9. What are 9. Elements are elements? substances made from just one kind of an atom. •There are 90 different types of elements in nature. •More than 20 elements are man made. Element Discussion •There are 90 different types of elements in nature. •More than 20 elements are man made. •It it is important to remember that when looking at the periodic table of the elements, “naturally occurring” does not necessarily mean “abundant.” Many naturally occurring elements are in fact quite rare, although some were once more abundant. Levels of elements also change depending on where you are: helium. For example, is rare on Earth, but abundant around the Sun. 10. What is the Periodic Table of Elements? 10. The periodic table is an arrangement of elements according to their atomic numbers. 11. What is an atomic number? 11. An atomic number is the number of PROTONS in the nucleus. 26 Fe Iron 55.845 12. What is a chemical symbol? 12. The first letter is always an upper case and the others are lower case. letter is always upper case and others are lower case A hydrocarbon ( this atom is natural gas) 13 What is atomic mass? 13.Atomic mass is: • Protons + Neutrons 14. How are metals and non metals arranged on the Periodic Table? 14. Non metals are located on the right and metals on the left. What are ionic bonds? 15. 15. Ionic bonds are formed by the attraction between two oppositely charged ions. • Usually occurs between positive metals and negative nonmetals. • Common example: table salt What are covalent bonds? 16. 16. Covalent bonds are bonds in which atoms share electrons. • H2O is an example 17.What is a molecule? 17. A molecule is formed when two or more atoms join together chemically. Methane gas What is a compound? 17. 17. A compound is made of two or more elements that are chemically combined. What are characteristics of metallic bonds? 18. 18.High boiling points • Good conductors of electricity • Requires much energy to break apart ( usually) 19. What is a formula? 19. A formula lists how many of each element that makes up a compound. H2O = 2 Atoms of Hydrogen and 1 atom of Oxygen C6H12O6 = glucose How many carbon atoms? Hydrogen atoms? Oxygen atoms? What are mixtures? 20 20. Mixtures are combinations of substances that are NOT bonded. 21. What Is a heterogeneous mixture? 21 A MIXTURE is a combination of two or more substances that are not chemically united and do not exist in fixed proportions to each other. Most natural substances are mixtures. -------------If broken apart, could the parts be seen separately ( raisins, oats, etc) 22. What Is a homogeneous mixture? 22. Homogeneous mixture is when substances are mixed evenly throughout the solution. *Many homogeneous mixtures are commonly referred to as solutions. •What is a mixture? 23. What are the parts of a solution? 23. Parts of a solution include: solute – substance being dissolved solvent – substance in which the solute dissolves Unit 4 – Properties and Changes 34 1.What are physical properties? 1. Physical properties are observed through the senses. 35 2. Examples of Color, shape, hardness, Physical texture, etc. changes Density – amount of matter in a given volume Buoyancy – ability to float in water Ductility – ability to be stretched, bent, etc. without breaking Solubility – amount that will dissolve in another substance 36 • The Hindenburg Disaster 37 3. What are the characteristics of acids? 3. Acids: corrode metals taste sour pH of 1-6 (7 is neutral) 4. What is the 4. Acids form relationship between hydrogen ions acids and water? when dissolved in water 38 39 40 5. What are the 5. Bases: characteristics of feel slippery bases? taste bitter react with fats (good for soap) pH of 8-14 41 6. What is the relationship between bases and water? 6. Bases form hydroxide ions when dissolved in water (also called alkaline) 42 43 7. Acids and 7. React to form salt and bases………… water. 8. PH SCALE 8. 44 9. What are physical changes? Physical changes do not change one substance to another ( i.e. bending, breaking) 9. 45 46 10. List 10. Solid: the states has definite shape and volume; particles vibrate without moving around or phases Liquid : of matter. has definite volume but not shape; particles are touching and move freely Gas: has no definite volume or shape ;particles are far apart and move very rapidly Plasma: superhot charged particles; stars Bose-Einstein Condensate – super cold and super dense solid 47 48 49 11What is melting? 12. What is evaporation ? Melting occurs when solids forms liquids. 11. 12. Evaporation occurs when liquids develop into gases. 50 13. What is condensation? 13. Condensation occurs when gases form into liquids. 51 14. What is freezing? 14. Freezing occurs when – liquids become solids 52 15. What is sublimation? 15. Sublimation occurs when solid forms into gas (skips liquid) 53 16. What is deposition? 16. Deposition occurs when gases form into a solid 54 55 56 57 19. Describe chemical reactions. 19 . Chemicals react to form different chemicals All reactions either release energy or absorb energy Law of Conservation of Matter : matter cannot be created or destroyed whatever matter goes in must come out 58 59 60