2. Matter and its Changes

3. Atoms Matter is made up of atoms Matter is anything that takes up space and has mass Atoms are the “building blocks” of life

4. Forms of matter that contain only one type of atom are called elements Atoms combine to form many different types of matter

5. Structure of an Atom Proton Electron (electron cloud) Neutron Mass Number = Protons + Neutrons Atomic Number = Number of protons

7. Isotopes When the number of protons in an atom changes it becomes a different element Atom is electrically neutral when the number of electrons and protons are the same. Atoms of the same element that have a different number of neutrons are called isotopes Ex. C 12 = 6p +6n C 14 = 6p + 8n

9. Ions Electrically charged atoms are called Ions The number of protons is not equal to the number of electrons Ions are attracted to each other when they have opposite charges Ex. Na + + Cl - = NaCl = salt Ex. Na + + F - = Sodium Fluoride for toothpaste

10. Combinations of Atoms

11. Atoms combine by sharing their outermost electrons in their electron clouds When two atoms are combined a molecule is formed

12. Bonds Ionic Bond – Positive and Negative ions combine and electrons are transferred –Ex. NaCl Covalent Bond – Electrons are shared –Ex. H 2 O

14. Combinations of Atoms

15. How Atoms Combine When at least two atoms are combined a molecule is formed There are two ways in which atoms combine to form molecules and compounds

16. Ionic Bonding Positive and Negative ions combine and electrons are transferred Example: Na + and Cl - = NaCl

17. Covalent Bonding In covalent bonding electrons are shared Example: 2H + O = H 2 O

18. Compound A type of matter that has properties different from the properties of each of the elements in it Example: Na (metal) + Cl (gas) = NaCl (solid salt) Example: 2H (gas) + O (gas) = H 2 O (liquid water)

19. Mixture Many different substances that when mixed together, each substance retains its own properties Examples: sand, air and salad

20. Solution When one substance of a mixture is dissolved in another substance it is a solution Examples: tea w/ sugar, salt water

21. Chemical properties describe how one substance changes when it reacts with another Examples: iron and oxygen = rust Physical Properties can be observed or measured without changing the substance Examples: color, shape, size, density and texture

22. If energy is added or taken away, matter changes phases

23. Matter can change by: 1. Increasing or decreasing the temperature Ex: freezing water turns it to a solid (ice) 2. Increasing or decreasing pressure Ex: Pressure to ice cube changes it to liquid

24. 4. Liquid to a solid: freezing point 5. Liquid to gas: evaporation point 6. Only substance that occurs naturally as a solid, liquid, and gas: Water

25. Changes of State freezing Increasing Energy Gases Liquids Solids boilingcondensing melting Sublimes deposition

26. Let us consider how the particles are arranged in the 3 states of matter. (phases) Particles have slightly more energy so are able to move randomly around each other and are spaced slightly further than in a solid. However they do not have sufficient energy to overcome the attractive forces between them so cannot escape from each other completely. Particles arranged in a regular, close-packed fashion. They have little energy, so simply vibrate about fixed positions, unable to overcome the attractive forces between them. LiquidSolidGas Particles have much more energy so have overcome all attractive forces between them. They move around very fast in a irratic fashion, colliding occasionally. They are much more spread out then in the solid or liquid state

27. Plasma Plasma is like a gas, but the atoms are made up of free electrons and ions. Plasmas are not common on Earth, however you may have seen plasma. –Northern lights or lightning

28. State Changes or Phase Change When a substance changes state, it is undergoing a physical change, there is no new substance formed. Physical changes unlike chemical changes are easy to reverse. Energy is required to turn from solids to liquids, and liquids to gases. In order to gain greater freedom of movement, the forces between the particles must be overcome. Energy is given up as gases turn to liquids, and liquids to solids. They move less freely and are held together more strongly.

29. Density

30. What is density? The measure of the mass of an object divided by its volume. The measure of the mass of an object divided by its volume.

31. Energy from Atoms 1. What is nuclear energy? - Alternate energy source produced from atomic reactions 2. How fission produces nuclear energy: - Splitting the nucleus of atoms in heavy elements

32. 3. Most commonly used fuel in nuclear power plants: - Uranium 235 Where is it found? - Sandstones in the Rocky Mountains

33. 4. Major source of nuclear waste: - Radioactive material Most common method of storing nuclear waste: - Power plants Can remain active for 10,000 years

34. Two advantages to storing nuclear waste at Yucca Mountain: 1. Remote area (deserted) 2. Water table is far below storage facility

35. Two disadvantages to storing nuclear waste at Yucca Mountain: 1. Earthquakes could destroy storage facility 2. Large amount of nuclear waste in one area