MATTER ATOMS, MOLECULES, ELEMENTS, AND COMPOUNDS

1. MATTERATOMS, MOLECULES, ELEMENTS, AND COMPOUNDS

2. Matter Matter is anything that has mass, volume and takes up space. Matter is made up of tiny particles called atoms and molecules .

3. States of Matter • Gas • Gasses have no definite shape or volume. • Particles move very fast and have almost no attraction to each other. • Solid • Have a definite shape and volume • Particles have a strong attraction to one another • Liquid • Have a definite volume but not a definite shape • Particles move fast enough to slip past each other. • Plasma • Super heated gasses • Stars, lightning Animated images are from http://www.chem.purdue.edu/gchelp/

4. Two Types Solids Crystalline • Have three dimensional arrangement • Have repeating rows • EX. Iron, diamonds and ice Amorphous • Do not have a special arrangement of particles. Each particle has its place but they are not organized • EX. Glass, rubber, and wax

5. Liquids • Viscosity is another property of liquids • Viscosity is the resistance of a liquid to flow. • The stronger the attraction of between the molecules of a liquid the more viscosity the liquid has like honey and oil. • Surface Tension is a property of liquids. • Surface tension is the force that acts on the surface or top of a liquid, tends to minimize the area of the surface. • Surface tension sometimes causes liquids to form spherical drops like rain.

6. Democritus and the Atoms Democritus – lived in Greece in 460BC (2,500 years ago) He asked this question: “If you break a piece of matter in half, and then break it in half again, how many breaks will you have to make before you can break it no further?” Democritus believed that at some point you would reach the smallest possible bit of matter that could not be split any further. He called this matter the atom. The word atom comes from the Greek word atomos which means cannot be split.

7. Unfortunately, Democritus’ theory was not taken seriously because another Greek philosophers, Aristotle, dismissed his idea as worthless. Democritus' Atomic Theory ‍1. All matter consists of invisible particles called atoms. ‍2. Atoms are indestructible. ‍3. Atoms are solid but invisible. ‍4. Atoms are homogenous. Homogenous – a Greek word that means "same kind." ‍5. Atoms differ in size, shape, mass, position, and arrangement.

8. Structure of an Atom • Atoms are mostly empty space • The three main parts of an atom are electrons (-), protons(+) and neutrons (N). • Most of the mass of an atom is in the center area called the nucleus. • Electrons have less mass than protons and neutrons. • The same number of electrons and protons are in each atom. • There are about 100 different kinds of atoms. Atomic Model

9. Molecules • How many hydrogen atoms can fit on the head of a pin? About five million million hydrogen atoms! (5,000,000,000,000 which is 5 trillion) • Molecules are made of two or more atoms bonded together. • Atoms in a molecule are held together by links called bonds. • Oxygen molecules in the air are made of two oxygen atoms bonded together. • Molecules of water are made up of two kinds of atoms. Each molecule is made of two hydrogen atoms and one oxygen atom. Oxygen Molecule Water Molecule

10. Silver Sulfide Silver Sulfur

11. Two Types of Molecules • Molecules in living things are called organic molecules. • All organic molecules contain atoms of carbon. EX. Methane, Ethane, Propane, Butane • The second type is called polymers. Polymer molecules become long by repeating over and over again! • Our clothes are made of polymers. Some come from nature like cotton and wool. Others are made in factories such as nylon and rayon. Organic Chain Polymer Chain

12. Elements If a hydrogen atom has one proton, how many electrons will it have? • Elements are materials made of one kind of atoms. (EX. iron in nails, helium in balloons and iodine in medicines) • Atoms of each element have different physical and chemical properties. • Atoms of each element have different numbers of protons. EX. Hydrogen has 1 proton and Uranium has 92 protons.

13. The number of protons are equal to the number of electrons. • The number of electrons in the atom of an element give the element its chemical properties. • The different number of electrons cause atoms to form bonds in different ways. • Elements can be made of single atoms or they can be made of molecules. Helium Oxygen

14. Compounds • If atoms of a molecule are the same it is an element. • If atoms of a molecule are different it is called a compound. • The particles in a compound are always made of molecules, not atoms. Because the particles of a molecule have more than one kind of atom.

15. Review • Atoms are always elements. • Two or more atoms form molecules. • Elements can be separate atomsor they can be in the form of molecules. • Elements combine to form compounds. • Compounds are made of two or more elements.

16. Kinetic Energy of Matter • Molecules are always moving. This is known as kinetic energy. • Molecules are moving due to a temperature increase or decrease. • The greater the internal energy, the higher the temperature of that material. • Heat and temperature are not the same. • Heat is the movement of energy flow between objects of different temperature.

17. Change of State • A change of state is the change from one physical form to another. • All changes of state are physical changes. • EX Ice, liquid water and steam are all the same substance – water. • Particles have different amounts of energy in each state. • EX Liquid water has more energy than Ice, steam has more energy than liquid water. • To change from one state to another, energy must be added or removed.

18. Changes of State • Melting – solid to liquid – energy increases • Freezing – liquid to solid – energy decreases • Vaporizing – liquid to gas – energy increases • Boiling – vaporizing from both within and the surface of a liquid. • Evaporating – Liquid to gas from the surface of water – energy increases • Condensation- gas to liquid – energy decreases • Sublimation – solid to gas- energy increases • Deposition – gas to solid – energy decreases Carbon Dioxide CO2

20. Chemical and Physical Property and Change • Physical Property - matter that can be observed or measured without changing the matter’s identity. A physical property of copper is that it is a good conductor of electricity • Examples - Magnetism, conduct electric, strength, and flexibility, change of state, solubility, ductility (pulled into wire), density (the amount of matter in a given space) and malleability (pounded into thin sheets)

21. Physical Change – is a change that affects one or more physical properties of a substance. For example crushing a coke can does not change the can into a new substance -it just changes the can physically. • More examples: changing water to ice or and gas. Dissolving sugar into water, the sugar seems to disappear, but if you heat the mixture, the water will evaporate and you would see that the sugar is still there!

22. Chemical Properties – describes matter based on its ability to change into new matter that has different properties. • For example flammability is a property, when wood burns, ash and smoke are created. Ash and smoke cannot burn so they have the chemical properties of nonflammability. • Another example, iron on an old car has the chemical property of reactivity with oxygen. When iron is exposed to oxygen, it rust. • The bumper of the car looks new because it is made of chromium. Chromium has the chemical property of nonreactivity with oxygen.

23. Chemical Change – happens when one or more substances are changed into new substances that have new properties. Their composition changes. • For example if you tear paper or cut wood it is physically changed it is still paper and wood, but if you burn paper or wood a chemical change takes place and both become a new substance called ash.

24. Compounds, Mixtures and Solutions Compounds are composed of two or more elements that are chemically combined. • Elements combine by reacting to, or undergoing a chemical change, with one another. • EX. Water – hydrogen and oxygen • Salt – sodium and chlorine • Carbon dioxide – carbon and oxygen • Backing soda – sodium, hydrogen, carbon and oxygen • Vinegar – hydrogen, carbon and oxygen Compounds make up the food you eat, the school supplies you use, the clothes you wear and even you!

25. Mixturesare a combination of two or more substances that are not chemically combined. • In some mixtures you can see each substance like pizza. • In other mixtures, such as salt water you cannot see the components. Separating Mixtures Physically • Some mixtures can be separated physically. EX. Pizza - if you don’t like mushroom you can pick them off. If you are eating trail mix you can take out the raisins.

26. Three common ways to separate mixtures: Distillation – separates mixtures by boiling ex. Pure water being distilled from salt water. Magnets – can be used to separate a mixture of the elements iron and aluminum. Iron is attracted to the magnet but aluminum is not. Centrifuge – separates mixtures by the densities of the components. Ex. Blood can be separated into plasma and red blood cell. (plasma on top)

27. Solutions – are mixtures that appears to be a single substance. • Solutions are composed of two or more substances. • Dissolving – is the process in which particles separate and spread evenly throughout a mixture. • Solute – is the substance that is dissolved. • Solvent - is the substance in which the solute is dissolved. Water is called the universal solvent because more substances dissolve in water than in any other chemical. • Ex. Salt water • Salt is the solute • Water is the solvent

28. Atoms • Protons (+) charge – have the more mass than electrons – they are found in the nucleus. • Neutrons (N) no charge – they have a little more mass than protons- they are found in nucleus. • Electrons (-) negative charge – they are found in the electron cloud. Compared to protons and neutrons, electrons have very little mass. The mass is so small it is usually thought of as zero. • Protons (+) and electrons (-) cancel each other out, so that the atom is neutral. • http://ed.ted.com/lessons/just-how-small-is-an-atom

29. What happens if the atom has unequal numbers of protons and electrons? • The atom becomes a charged particle called an ion. • If an atom losses one or more electrons it becomes positively charged ion. • If an atom gains one or more electrons it becomes a negatively charged ion. • Happens during the chemical reaction to create salts. Na + ion Cl - ion

30. What is the atomic number of an atom? • The number of protons in an atom’s nucleus. • All atoms of one type of element have the same atomic number (number of protons) • Ex. every atom of carbon has the atomic number of 6 because each carbon atom has 6 protons. What are isotopes? • Isotopes are atoms that have the same number of protons, but different number of neutrons.

31. Some isotopes of an element have special properties because they are unstable. • Unstable isotope atoms are unstable because the nucleus changes over time. • This type of isotope is radioactive. Radioactive isotopes fall apart or decay at a specific rate. • For example: Carbon 14 dating is a way of determining the age of certain archeological artifacts of a biological origin up to about 50,000 years old. It is used in dating things such as bone, cloth, wood and plant fibers that were created in the relatively recent past by human activities.

32. http://ed.ted.com/lessons/the-genius-of-mendeleev-s-periodic-table-lou-sericohttp://ed.ted.com/lessons/the-genius-of-mendeleev-s-periodic-table-lou-serico http://www.youtube.com/watch?v=kuQ0Um4Wcz0

33. Element Clips • http://www.youtube.com/watch?v=r7hO-1ItqXw • http://www.youtube.com/watch?NR=1&v=v1TfPDlA1xE&feature=fvwp • http://ed.ted.com/lessons/solving-the-puzzle-of-the-periodic-table-eric-rosado

34. Arrangement of Elements • Atomic Number – number of protons in a atom • Symbol – Usually corresponds to the elements name, but not always. (1 to 3 letters) • Name • Mass Number – Mass of protons and neutrons in the atom.

35. Families or Groups – vertical columns. All elements in a family have similar properties, usually react to the same chemical reactions, may even look the same and may be used for the same purposes.

36. Periods – horizontal rows. There are seven periods in the periodic table.

37. Metal and Nonmetals and Metalloids Metals (left) – are good conductors of heat and electricity. They have shiny, metallic luster, and they can be pounded into shapes or pulled into wire. Nonmetals(right) – are poor conductors, usually have dull or earthy luster. When pounded, nonmetals usually shatter or form powder. Metalloids( touch the bold stepped line) – have characteristics of both metal and nonmetals.