* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chemistry Review- Answer all questions on loose
Survey
Document related concepts
Transcript
Chemistry Review- Answer all questions on loose-leaf!!!! 1. Know the “KEY TERMS” from the vocabulary list given at the beginning of the unit. (41 key terms) 2. Compare physical properties and chemical properties. (Similarities and differences) Both properties describe a substance’s characteristics. All matter has both chemical and physical properties. If a chemical change occurs, the new substance will have new chemical and physical properties. A physical property is a property that can be measured or describes a physical state. They include color, mass, state, ability to conduct electricity, density, malleability, magnetism, etc. A chemical property describes the changes made to the chemical makeup of a substance. Properties include combustion, toxicity, flammability, etc. 3. Some of the physical properties of pure water are listed below. Which properties are qualitative and which are quantitative? a) Pure water is a very poor conductor of electricity. Qualitative b) The volume of a sample of water is 26.8 mL. Quantitative c) The normal boiling point of water is 100oC. Quantitative d) Small depths of water are transparent to light. Qualitative 4. a) What properties indicate a physical change has occurred? Change in physical state, size, shape, temperature, texture, etc. b) What properties indicate a chemical change has occurred? There has been a change to the chemical makeup of the original substance. A precipitate may be formed, color change, heat is absorbed or given off, bubbles, gas is produced, a substance disappears, a new odor, etc. 5. Which of the following are physical properties and which are chemical properties? a) Lead is a relatively soft metal. Physical property b) Copper wires are good conductors of electricity. Physical property c) An iron nail rusts. Chemical property d) Tums neutralizes stomach acid (heartburn). Chemical property 6. Classify each of the following as a physical change or a chemical change. a) Frying an egg. Chemical change b) Percolating coffee. Physical change (dissolving) c) Letting socks dry. Physical change (evaporation) d) Toasting bread. Chemical change e) Growing a plant. Chemical change f) Silver cutlery tarnishing over time. Chemical change 7. What were the major contributions of the following scientists to the study of chemistry: a) Dalton (include Dalton’s atomic theory) Main points are: - Elements are made of small particles called atoms. Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in size, mass and other properties. Atoms cannot be subdivided, created or destroyed. Atoms of different elements combine in simple-whole-number ratios to form chemical compounds. In chemical reactions, atoms are combine, separated, or rearranged b) Thomson He discovered the electron and isotopes. He demonstrated that the atom consisted of subatomic particles though his experiments with cathode rays. He proposed the Plum Pudding Model where the atom is composed of electrons surrounded by a soup of positive charge to balance the electrons negative charge. c) Rutherford He developed the Rutherford model as a model for the structure of the atom. He created it in response to the plum pudding model made by Thomson, which he believed to be incorrect. His model contained a nucleus, which contained a high concentration of subatomic particles in a small area and made up the bulk of the atoms mass. The electrons then surrounded the nucleus in a cloud. d) Bohr He took Rutherford’s model and further adapted it to create the Bohr-Rutherford Model. The atom still has a small, positively charged nucleus made of protons and neutrons surrounded by electrons that travel in circular orbits around the nucleus. Most of the mass of the atom is found in the nucleus. 8. Compare and contrast the subatomic particles. (Size, location, charge, mass, atomic number, atomic mass) Electrons Located in shells -1 charge Smallest subatomic particle No mass +1 charge Protons Equal to the atomic number Located in the nucleus Same relative size Add to make up the atomic mass Mass 1amu Located in the atom. No charge Neutrons 9. Write the chemical symbol of the following elements. a) Potassium K b) Calcium Ca f) Zinc Zn g) Tin Sn c) Uranium h) Silicon U d) Lead Pb e) Copper Si i) Magnesium Mg j) Argon Cu Ar 10. Write the name of the element for the following chemical symbols. a) P Phosphorus b) Ar Argon f) W Tungsten g) Ni Nickel c) Fe Iron h) I Iodine d) Hg Mercury i) B Boron e) Au Gold j) Ag Silver 11. Determine the number of protons, electrons and neutrons from the following information: a) Atomic Number of 78, Atomic Mass of 195. P = 78 b) Atomic Number of 60, Atomic Mass of 144 P = 60 c) Atomic Number of 114, Atomic Mass of 289 P = 114 E = 78 N = 117 E = 60 N = 84 E = 114 N = 175 12. Determine the atomic number and atomic mass from the following information. a) Protons = 32 b) Protons = 40 c) Protons = 101 Electrons = 32 Electrons = 40 Electrons = 101 Neutrons = 41 Neutrons = 51 Neutrons = 157 #32 73 amu #40 91 amu #101 258 amu 13. Draw Bohr diagrams for the following elements and properly label them with their element symbol, valence, period and family. a) Lithium P=3 N=4 Li Valence: 1 Period: 2 Family: 1 b) Oxygen P=8 N=8 O Valence: 6 Period: 2 Family: 6 c) Magnesium P = 12 N = 12 Mg Valence: 2 Period: 3 Family: 2 14. How does electron structure of the noble gases help to explain their chemical properties? Noble gases are stable, generally non-reactive elements. Their structure explains this characteristic seen in the family. Their valence shells are always full, leaving the atom no desire to gain or lose electrons by reacting with other atoms. 15. List 3 properties of each chemical family. Organize the information into a chart like the one shown below. Alkali Metals Li, Na, K, Rb, Cs, Fr Highly reactive, unstable Shiny, silvery React with water to produce alkaline solutions 1 valence electron Softer than other metals Alkaline Earth Metals Be, Mg, Ca, Sr, Ba, Ra Very reactive Occur naturally Silvery, soft metals 2 valence electrons Transition Metals Ag, Au, Co, Cu, etc 38 elements in the group Metals Ductile Malleable Conduct electricity and heat Valence electrons are special! Strong Shiny Chalcogens Halogens Noble Gases O, S, Se, Te, Po A.K.A. the oxygen family. Tend to form copper-ore or other ores. 6 valence electrons Nonmetals Se, Te, Po are metalloid semiconductors F, Cl, Br, I, At 7 valence electrons Very unstable and reactive Do not conduct electricity Bind with alkali metals or themselves ! He, Ne, Ar, Kr, Xe, Rn Very, very low reactivity stable Full valence shell Colorless and odorless Can be excited by electricity to create interesting colors. 16. a) Who created the first version of the periodic table? Dmitri Mendeleev b) What was this organization of this table based on? The organization of that table was based on the atomic mass and properties of the elements. c) The modern periodic table is organized into rows and columns. What are the rows and columns called on the modern periodic table? Rows are called periods and the columns are called groups. d) What information do the periods give you about the structure of all of the atoms in that period? The period numbers indicate the number of electron shells in the atom. e) What information do the groups give you about the structure of all of the atoms in that group? The group numbers indicate the number of outer-shell electrons (valence electrons) of all the atoms in the group. 17. a) Compare the properties of metals and nonmetals. (Similarities and differences) Similarities: color varies, many elements are not magnetic, metalloids include elements with properties of metals and nonmetals. Metals: shiny, malleable, conductors Nonmetals: dull, brittle, do not conduct electricity. b) List all the metalloids on the periodic table and state 2 characteristics of metalloids. Each of these elements are metalloids: Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te), Polonium (Po), Astatine (At). Some characteristics of metalloids are: Can be shiny or dull May conduct electricity Poor conductors of heat They are brittle (easily breakable) Not ductile (cannot be drawn into a long thin wire) 18. a) Which families are the most reactive on the periodic table? Why? The alkali metals (group 1) and the halogens (group 17) are the most reactive because the alkali metals have one electron in their outer shell that they desperately want to get rid of. The halogens have 7 outer shell electrons and they need only one extra electron to complete its outer shell. b) Which families are the least reactive? Why? The noble gases (group 18) are the least reactive family because they have a full outer shell. 19. What is the difference between elements and compounds? Elements are a type of pure substance that cannot be broken down into simpler parts by ordinary chemical needs. (Ex. Oxygen, gold) Compounds are pure substances made up of two or more elements that are chemically combined. (Ex. CO2 consists of 2 elements, carbon and oxygen) 20. What information is given in a chemical formula? The information given in a chemical formula is the name of each element in the compound and the number of atoms of each element in the compound. 21. State the name and number of each element in the following compounds: a) AlN Aluminum 1 Nitrogen 1 b) SbH3 Antimony 1 Hydrogen 3 e)(UO2)2(OH)4 Uranium 2 Oxygen 8 Hydrogen 4 f) Zn(CN)2 Zinc 1 Carbon 2 Nitrogen 2 c) Ca(NO3)2 Calcium 1 Nitrogen 2 Oxygen 6 g) SO2Cl2 Sulfur 1 Oxygen 2 Chlorine 2 d)(C2H5)2 Carbon 4 Hydrogen 10 h) KTiOPO4 Potassium 1 Titanium 1 Oxygen 5 Phosphorus 1 22. In each pair of elements, which is the more reactive element? Explain your choice based on the properties of the periodic table. a) Barium or Calcium - Both Ba and Ca are part of group 2, the alkaline earth metals. The reactivity increases as you move down the group. Calcium is less reactive as it is in period 4 and Barium is in period 6. b) Boron or Argon - Boron is more reactive than argon since argon is a noble gas. Noble gases are the least reactive elements since they have complete outer shells. Boron is also more reactive because it only has 3 outer shell electrons and must react with something to end up with a full shell. c) Sodium or Magnesium - Both Na and Mg are in the same period on the periodic table, but Na has only one valence electron (group 1-Alkali metals) making it violently reactive. Na is very close to a full electron shell, it only has to lose one electron and that will happen more readily than Mg losing two (group 2 –Alkaline earth metals). It is harder for Mg to lose two electrons so the reaction isn’t quite so volatile. 23. a) What are isotopes? Isotopes are any of two or more forms of an element that have the same number of protons but a different number of neutrons. b) Explain how the existence of different isotopes of an element would affect the element’s relative mass in the periodic table? An element’s relative mass in the periodic table is an average of the masses of the isotopes of that element. The proportion of each isotope is factored into the element’s atomic mass. c) There are 10 isotopes of tin. State at least two ways in which atoms of these isotopes would be alike? All of the isotopes of tin would have the same atomic number, the same number of protons and the same number of electrons (if the atom is neutral) d) Naturally occurring isotopes of both rubidium (Rb) and strontium (Sr) are found with the same mass number, 87. Explain how this is possible. Rb and Sr could have the same atomic mass because of the different number of neutrons in each atom. Rb has an atomic number of 37, 37 protons and 50 neutrons (if the atomic mass is 87 amu). Sr has an atomic number of 38, 38 protons and 49 neutrons (if the atomic mass is 87 amu). 24. a) Which element was likely discovered first, Neon, Nickel or Nitrogen? Explain. Nitrogen was likely discovered first because its chemical symbol is a single letter, where as both Neon and Nickel have two letters for their symbols. Both nickel and neon would only have N if either was discovered prior to nitrogen. b) Which element was likely discovered first, Nobelium or Niobium? Explain. Based on naming rules Nobelium was likely discovered before Niobium. N was taken for nitrogen, so Nobelium’s symbol is No. Niobium could not be given N due to nitrogen, or Ni due to nickel, so the first possibility would have been No, but No must have been taken by Nobelium so Niobium’s symbol is Nb. c) If a new element “Brainium” were discovered, what might the element symbol be? Explain your choice. “Brainium” would need have Bn as its chemical symbol. B is taken by Boron, Br is taken by Bromine, Ba is taken by Barium and Bi is taken by Bismuth. The symbol must be 2 letters, so Bn would be the next available set of letters for Brainium. 25. Complete the table. Element Name Element Symbol Atomic Number Atomic Mass Number of Protons Number of Electrons Number of Neutrons Magnesium Mg 12 24 12 12 12 Lithium Iodine Oxygen Sodium Li I O Na 3 53 8 11 7 127 16 23 3 53 8 11 3 53 8 11 4 74 8 12 Group Period 2 3 1 17 16 1 2 5 2 3 Family Name Alkaline Earth Metals Alkali Metals Halogen Chalcogen Alkali Metal