1. STAR Testing Review8th Grade ScienceStructure of MatterPeriodic Table
2. Solids, Liquids and GasesSTATES OF MATTER!!!
3. All matter is made of atoms andmolecules, which we will call particles. All particles vibrate or move because theyhave energy. The state of matter they are in depends onhow strongly they are attracted to eachother.
4. Matter that has defined shape and volumeis considered to be solid. Particles in a solid have high attraction foreach other. The particles vibrate in placeand don’t have enough energy to get awayfrom each other Two types of solids: Crystalline – particles in a repeating formation Amorphous – randomly oriented particles
5. A solid has defined space and volume. Itwill not take the shape of the containerunless energy is expended to make it adifferent shape.
6. Liquids have defined volume but not definedshape The particles in a liquid can slide past eachother, and are less attracted to each other than ina solid. Two properties of a liquid: Surface tension – the liquids tend to ball up and sticktogether Viscosity – a measure of how well the liquid flows.Water is low viscosity, molasses is high viscosity.
7. A liquid has defined volume but will takethe shape of the container. They have more energy than a solid
8. Gases have no defined shape or volume.They can be compressed by pressure andchange their volume and will fill all thespace they are given. The particles in a gas are moving fastenough to break away from each other andeach particle moves independently. In a gas, there is empty space betweenparticles. Pressure can effect all gases. High pressuremeans that you have forced a large amount ofgas particles in a small space – like inside atire or basketball.Gases
10. What IS phase change?? Phase change is the change of the state (solid, liquid, gas)that the matter is in. This change begins by either taking away energy or addingenergy to the particles of matter. These changes can start at any state and end at any state.
11. Melting! Melting involves ANY solid becoming aliquid. Melting is ENDOTHERMIC- energy in theform of heat is ENTERING the reaction. The molecules are gaining enough energyto break away from their rigid structure andmove among the group.
12. Melting! Every substance has a “melting point”. The melting point is the temperature atwhich the substance begins to melt. The melting point of a substance is aphysical property. **ALL substances have DIFFERENTmelting points! It’s not all the same aswater!!!!!!!
13. Freezing Freezing involves ANY liquid becominga solid. Freezing is an EXOTHERMIC reaction-energy is EXITING the reaction in theform of heat (heat is leaving). The molecules are losing energy- andforced to stay in a rigid structure.
14. Freezing Every Substance has a “freezing point” The freezing point is the temperaturewhere the substance begins to freeze orsolidify. The freezing point of a substance is aphysical property and varies for eachsubstance.
15. Condensation Condensation is when a gas becomes aliquid. This is an EXOTHERMIC reaction-energy LEAVING in the form of heat. The molecules are losing energy andbecome a group again after being totallyindependent.
16. Vaporization Evaporation is any liquid becoming a gas This reaction is ENDOTHERMIC-energy is ENTERING in the form ofheat! The molecules are gaining SO muchenergy that they are becoming totallyindependent and fly away on their own!
17. Vaporization There are two types: Boiling Evaporation
18. Boiling Boiling is… a relatively quick change from a liquid to a gas Occurs by adding a lot of heat all at once Happens at a specific temperature The change happens within the ENTIRE fluid-all molecules are being affected.
19. Evaporation Evaporation is… A relatively slow process Occurs overtime from gas particles crashingonto the surface of the liquid and passing ontheir energy to the liquid molecules. No specific temperature associated with thischange (can happen at room temp!) Happens only on the surface of the liquid.
20. Particles in a gas state are not bound to eachother and have the most energy.Example of a Gas
21. The parts of an Atom
22. The atom An Atom: The most basic unit of matter. An atom has a dense nucleus and a cloud ofnegatively charged electrons around it. If matter is what everything is made of, andmatter is made of atoms… Then, everything is really made of atoms!
23. The Parts: Electron: A subatomic particle with a negativeelectrical charge. (no mass) Nucleus: The dense center of an atomcontaining protons and neutrons. A Proton: A subatomic particle within thenucleus of an atom that has a positive charge. A Neutron: A subatomic particle within thenucleus of an atom that has a neutral charge.
24. Energy Level The energy level of an atom is as follows: 2,8,8 The first shell has two electrons The second shell has 8 electrons The third shell has 8 electronsMEMORIZE: 2,8,8!!!!!!!!!!
25. Atomic Number The atomic number is thenumber mainly associatedwith the element andrepresents the number ofprotons present in theatom.
26. Mass Number The total number ofprotons and neutrons. The mass of an atom comesfrom the protons andneutrons. Therefore, the mass includesthe masses of each addedtogether. This number can be found atthe bottom, typically.Mass Number
27. Element Each of these are ELEMENTS!!! When you put them together, they becomesomething different…
28. Compounds! Remember that compounds are merely theresult of combining two or more elements. H2O is a compound! NaCl is a compound! REMEMBER- compounds have differentproperties than the elements they are madeof when alone. Hence why table salt (NaCl) doesn’t blow up
29. How can you identify Elements? What are the elements in the followingcompounds? H2O NaCl CO2
30. Periodic Table!! Remember that beautiful display ofelements? It’s time to remember how to use it!
31. Time to test your knowledge! How many groups are there? Which group number are the noble (inert) gases? Why are the noble gases important? Where are the metals located? Where are the semi-metals? Where are the Alkali metals located? Where are the Alkaline Earth metals located?
32. Review of Chemical BondingIonic, Covalent, Metallic
33. Ionic Bonds Ionic Bonds occur between metals and non-metals. Metals always lose their extra valenceelectrons and non-metals always try to gainextra valence electrons. Metals become positive ions and non-metals become negative ions.
34. Ionic Bonds Properties of Ionic Bonds: Brittle (breaks easily) Extremely high melting and boiling points Conduct electricity Form between ions (metals & non-metals)
35. Covalent Bonds Covalent bonds occur between non-metalsand non-metals Since non-metals are always trying to findextra electrons rather than get rid of them,Covalent bonds always share their electrons(how nice of them!)
36. Covalent Bonds Properties of Covalent Bonds Malleable (can be formed/manipulated) Low melting and boiling points Do not conduct electricity or heat
37. Metallic Bonds Metallic bonds occur between metals andmetals. Remember that all metals are always tryingto lose their extra electrons to becomehappy. In Metallic bonds metals “pool” theirelectrons and all become ions while“swimming” around in the pool of electrons(AKA the “sea of negativity”)
38. Metallic Bonds Properties of Metallic Bonds: Malleable Ductile (can be stretched into wires) Conducts heat and electricity