Atoms and Elements Review YOU ARE EXPECTED TO KNOW THE MEANING OF ALL THE FOLLOWING TERMS: ALCHEMY ELEMENT ATOM SUBATOMIC DEMOCRITUS DALTON THOMSON RUTHERFORD BOHR ELECTRON NEUTRAL PROTON NEUTRON ORBIT VALENCE AMU ATOMIC MASS ATOMIC NUMBER PERIODIC LAW PERIOD GROUP FAMILY MENDELEEV NON-METALS METALS OCTET RULE PURE MIXTURE COMPOUND MOLECULE DIATOMIC HETEROGENEOUS HOMOGENEOUS SUBSCRIPT COEFFICIENT FORMULA LAW OF CONSERVATION OF MATTER STATE/PHASE MELTING POINT BOILING POINT LUSTRE MALLEABILIITY DUCTILITY SOLUBILITY CONDUCTIVITY COMBUSTION CORROSION OXIDATION HYDRATION METALLOIDS PHYSICAL PROPERTY CHEMICAL PROPERTY PHYSICAL CHANGE CHEMICAL CHANGE PRECIPITATE S1-2-01: How did each person contribute to our understanding of matter? 1. Pick any two scientists (Thomson, Bohr, Rutherford, Dalton) and explain the differences in their contributions to Atomic Theory. Rutherford: Discovered the nucleus. Proposed that the atom is mostly space, but has a positive nucleus with electrons spinning around it. Bohr: Proposed that the electrons spin around the nucleus in orbits or energy levels. Thomson: Discovered the electron. Proposed the plum pudding model negative electrons embedded in the positive atom. Dalton: Proposed the first atomic model that matter is made of atoms; that all atoms of one element are the same; that elements have different atoms; and atoms can t be create or destroyed. S1-2-02: What is the basic subatomic structure of an atom? 2. Atoms are made up of three kinds of particles (fill in the blanks): Name Charge Location Relative Mass Actual Mass PROTON +1 NUCLEUS Unbelievably 1 amu small NEUTRON 0 NUCLEUS ELECTRON -1 ORBITS 1 amu 1/2000 amu Unbelievably small Even smaller than that!
S1-2-04: How do you use atomic mass and atomic number to identify parts of the atom? 3. Explain how you use the periodic table to find the number of electrons, protons and neutrons. Use sodium as an example. Use the atomic number (smaller number on the top) and the atomic mass (bigger number on the bottom). For example the periodic box for sodium has an 11 on the top and a 23.0 on the bottom. The atomic number represents the number of protons in the atom, and since atoms are neutral, also the number of electrons (in this case 11 protons and 11 electrons). The atomic mass is the number of protons and neutrons together in the nucleus. Since protons and neutrons each weigh 1 amu, then the atomic mass minus the number of protons will give you the number of neutrons (in this case 23 11 = 12 neutrons). S1-2-05: How do you draw an atom using a Bohr Diagram? 4. Draw s Bohr diagrams of an oxygen atom and of a lithium atom write the name and symbol below. 8p + 3p + 4n o 2e - 1e - Oxygen atom - O Lithium atom - Li 5. Draw Bohr diagrams of an oxygen ion and of a lithium ion write the name and symbol below. + 8p -2 3p + 4n o 2e - 1 + Oxygen ion - O 2- Lithium ion - Li 1+
S1-2-06: How is the Periodic Table organized for the elements and what patterns exist? 6. Label (using patterns) these groups of elements on the miniature periodic table: Element Pattern a)hydrogen b) Noble Gases c) Alkali Metals d) Halogens e) Metalloids S1-2-03: What are the symbols of the first 20 elements and other common ones? 7. What elements do the following symbols represent? (Try not to look at your Periodic Table) a) O Oxygen f) He Helium b) K Potassium g) P Phosphorus c) Hg Mercury h) S Sulphur d) Si Silicon i) Li Lithium e) F Fluorine j) Na Sodium 8. What are the symbols for the following elements? a) Copper Cu f) Gold Au b) Silver Ag g) Lead Pb c) Argon Ar h) Iron Fe d) Tin Sn i) Boron B e) Tungsten W j) Mercury Hg
S1-2-08: Why do families react differently during chemical reactions? 9. How does your knowledge of the Octet rule or the expression 8 is GREAT help to explain the lack of reactivity for the Noble (inert) gases? Atoms want to get a full outer shell by gaining or losing valence electrons to have 8 (Or 2 in the first shell like Helium). Noble gases already have a full outer shell so they don t need to gain or lose electrons and so they don t react. 10. Give the symbols and charges once these atoms react to become ions. a) Sodium symbol: Na charge: +1 b) Fluorine symbol: F charge: -1 c) Oxygen symbol: O charge: -2 d) Magnesium symbol: Mg charge: +2 e) Boron symbol: B charge: +3 f) Nitrogen symbol: N charge: -3 S1-2-09: How do you classify matter using the words: element, compound, atom, molecule, mixture and pure? 11. Find the words from the choices below which match the definitions (One will not be used): Chemistry, Matter, Mass, Volume, Element, Compound, Mixture, Atoms, Molecule a) ATOMS The smallest particle of an element b) MASS The amount of matter in an object c) ELEMENT A pure substance composed of only one type of atom d) MOLECULE The smallest particle of a compound e) VOLUME The amount of space an object occupies f) COMPOUND A pure substance that can be only be broken down by chemical means g) CHEMISTRY The study of matter h) MIXTURE Two or more substances which have been combined physically
S1-2-10: How do you use a formula to find the elements in the molecule and the number of atoms of each element? 12. Given the following formulas, how many of each element is in a molecule of that substance? a. H2O2 Type of Atom Number HYDROGEN 2 OXYGEN 2 b. Ca3(PO4)2 Type of Atom Number CALCIUM 3 PHOSPHORUS 1 2 = 2 OXYGEN 4 2 = 8 c. 2 C6H12O6 Type of Atom Number CARBON 6 2 = 12 HYDROGEN 12 2 = 24 OXYGEN 6 2 = 12
S1-2-07: What properties classify elements as metals, non-metals or metalloids? 13. List some physical properties to show how they would help identify metals or non-metals. METALS: High conductivity Malleable/ductile High lustre Mostly solids High melting/boiling point NON-METALS: low conductivity Brittle low lustre mostly liquids/gases low melting/boiling point S1-2-12: How do you identify physical or chemical change and if a chemical reaction has taken place? 14. Use your knowledge of the signs of a chemical reaction to explain how you know that lighting a piece of paper on fire is a chemical change, but melting snow is not. A physical change is only a change in state/phase or shape. None of the following signs are present: (The signs of a chemical reaction /chemical change) a. Change in colour b. Change in smell c. Change in energy d. Formation of a new gas e. Formation of a new solid (precipitate) f. Not reversible Paper on fire CHEMICAL change in smell, change in colour, not reversible, gas is formed, change in energy. Melting snow PHYSICAL reversible, no signs visible, just a change in phase/state
12. Which one of the following is a chemical change? a) You boil water to make dinner. b) You crack open eggs. c) You add a bit of vinegar and salt to the water. d) You poach the eggs by placing them into the water. e) You cut the eggs up to eat them. 13. Which one of the following is a physical change? a) Acid damages the surface of a car. b) Fresh paint on a car hardens overnight. c) The car burns up gasoline on a trip. d) The car explodes in a collision. e) The autowrecker crushes the car into a tiny cube. 14. Which of the following is a chemical property? a) Combustibility. b) Colour. c) Taste. d) Density. e) Malleability. 15. Which of the following is a physical property? a) Reactivity with oxygen. b) Spontaneously explosive. c) Oxidizing substance. d) Inert (non reactive). e) Ductility.