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CHEMISTRY

CHEMISTRY. Science 9. WHY STUDY CHEMISTRY?. In this unit we will be studying atoms, elements and compounds Brainstorm with a partner how you would complete the following sentences We are studying chemistry and atoms, elements and compounds because…….

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CHEMISTRY

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  1. CHEMISTRY Science 9

  2. WHY STUDY CHEMISTRY? • In this unit we will be studying atoms, elements and compounds • Brainstorm with a partner how you would complete the following sentences • We are studying chemistry and atoms, elements and compounds because……. • Studying chemistry is of importance in my life because……. • Some things in my everyday life that has to do with chemistry are……

  3. LESSON 1: SAFETY Science 9

  4. SAFETY IN THE SCIENCE CLASSROOM • You will be assigned 1 safety rule on pages 10-11 • Use the poster paper provided and felts/pencil crayons to make a poster with your safety rule • We will be putting these up in the classroom so take time to make it presentable • You will each present your safety rule to the class • We will have a short quiz at the end of the activity where you will gallery walk around the room to find the answers to the quiz

  5. WHMIS SYMBOLS • WHMIS: Workplace Hazardous Materials Information System • Symbols are used for chemicals • Tells us about the hazards of the chemical • There are 8 symbols • YES…you need to know these!

  6. LESSON 2: INVESTIGATING MATTER Science 9

  7. What is matter? • Matter: anything that has mass or volume • Mass: amount of matter in a substance or object (grams) • Volume: amount of space of a substance or object occupies (litres) • Matter can change in 2 ways: • Chemical change • Physical change

  8. Chemical Change • Chemical Change: change in matter when substances combine to form new substances • Example: when you light a sparkler it glows white because it contains magnesium and it glows white • Example: Hydrogen and Oxygen combine to form water (H20) • Example: Sodium and Chloride combine to form salt (NaCl) •  in each of these examples, a new substance is formed

  9. Physical Change • Physical Change: matter undergoes a change in appearance BUT no new substances are formed • Matter undergoes a change of state • 3 states of matter • Solid- matter has a defined shape and volume • Example- ice • Liquid- has volume but shape is determined by its surroundings • Example- water • Gas- mass and volume are determined by its surroundings • Example- evaporated water (steam)

  10. Kinetic Molecular Theory (KMT) • Kinetic Energy: energy of motion • All particles (solid, liquid and gas) are always in motion • KMT: the theory that explains what happens to particles when they change between states

  11. KMT: The Main Points • There are 4 main parts to the KMT theory • All matter is made up of small particles • There is empty space between all particles • Particles are constantly moving regardless of state • Solid- particles packed so close together that they only vibrate • Liquid- particles farther apart so they move more and slide against one another • Gas- particles are very far apart, they move quickly • Energy makes particles move • More energy…particles move faster

  12. KMT Demo • Volunteers Please!

  13. Temperature and Changes of State

  14. Temperature and Changes of State • Melting: solid  liquid at a certain melting point • Evaporation: liquid  gas • Deposition: gas  solid • Sublimation: solid  gas • Condensation: gas  liquid • Solidification: liquid  solid

  15. How do we describe matter? • To describe matter we observe the physical properties of a substance in 2 ways • Qualitative properties: properties can be described but not measured • Quantitative properties: characteristics that can be measured

  16. How do we describe matter? • Qualitative Properties • State- solid, liquid or gas • Color- what color is the substance? • Malleability- ability to be beaten into sheets • Ductility- ability to be drawn into wires • Crystallinity- shape or appearance of crystals • Magnetism- tendency to be attracted to a magnet

  17. How do we describe matter? • Quantitative Properties • Solubility- ability to dissolve in water • Conductivity- ability to conduct electricity or heat • Viscosity- resistance to flow • Density- ratio of a material’s mass to its volume • Melting/Freezing point- temperature of melting/freezing point • Boiling/Condensing Point- temperature of boiling/condensing point

  18. Pure Substance • Pure Substance: a substance made up of only one kind of matter (gold, water, oxygen) • 2 kinds of pure substances • Element- a pure substance that cannot be broken down or separated into smaller substances • Example: gold, oxygen • Compound- a pure substance composed of at least 2 elements • Example: water

  19. Assignment • Page 27 #1-16

  20. LESSON 3: ATOMIC THEORY Science 9

  21. Think-Pair-Share • Turn to a partner and discuss what you already know about atoms and the atomic theory • We will share out as a class to see what we already know about the atom

  22. Development of the Atomic Theory • The current view of the atomic theory tells us how an atom is constructed • There were 4 scientists that helped develop the current accepted atomic theory: Dalton, Thomson, Rutherford, Bohr • On a piece of paper and using pages 29-31 make notes of what these 4 scientists contributed to the atomic theory • You will have 15 min to do this then we will continue with the lesson

  23. JOHN DALTON(1766-1844) • Dalton’s Atomic Theory • All matter is made of small particles that we call atoms • Atoms cannot be created, destroyed or divided into smaller particles • All atoms of the same element are identical in mass and size • Atoms of different elements are different in mass and size • A compound is when atoms of different elements join together in definite proportions (ex- water)

  24. JJ THOMSON(1856-1940) • British physicist studied electric current in gas discharge tubes • 1897- discovered the electron as streams of negatively charged particles • ‘raisin bun’ model of the atom: a positively charged ball like a bun with negatively charged electrons embedded in it like raisins • This model was quickly changed with Rutherford’s research

  25. ERNEST RUTHERFORD(1871-1937) • 1909: Designed an experiment to probe inside the atom • Exposed a thin sheet of gold to a stream of heavy positive particles (alpha particles) • Used a fluorescent detector screen which lights up when struck by an alpha particle • Most particles went through the gold as expected • A few bounced backwards…he discovered the nucleus! • Discovered the nucleus, the proton and the neutron • A decade after his original experiment he concluded that the nucleus was made of 2 particles, a positive proton and a neutron with no electric charge

  26. NEILS BOHR(1885-1962) • Worked under Rutherford • He proposed that electrons surround the nucleus in energy levels or ‘shells’ • When electricity is added to neon gas the electrons gain energy and jump from low to high energy levels, when they drop energy/levels the release visible light  this proved that electrons exist in energy levels

  27. ATOMIC THEORY • So now we have a clear idea of what’s in an atom and how it was discovered • Atom: smallest particle of an element that still retains the properties of the element • The atom if composed of 3 subatomic particles: • Proton • Neutron • Electron

  28. MASS • Protons and neutrons have more mass than electrons • Electron mass is negligible compared to protons and neutrons

  29. ELECTRIC CHARGE • There are 2 types of electric charges: positive and negative • Protons  positive • Electrons  negative • Therefore, protons and electrons are attracted to one another • Charges add up to zero making the atom uncharged or neutral

  30. ATOMIC THEORY • Subatomic particles differ in mass and electric charge

  31. NUCLEUS • Tiny region at the centre of the atom • Positively charged because of protons • Contains neutrons with no charge • Protons and neutrons never leave the nucleus

  32. ELECTRON • Occupy shells that surround the nucleus • Negligible mass • Account for 99.99% of the volume • Not a fast moving particle, rather it exists like a spread out negative charge around the nucleus

  33. ASSIGNMENT • Page 37 #1-15

  34. LESSON 4: THE ELEMENTS Science 9

  35. A TOUR OF THE COMMON ELEMENTS • Recall elements have physical properties (ex-state and color) as well as chemical properties (ex-its ability to react) • The periodic table has 2 main types of elements, metals and non metals • Metals: typically hard, shiny, malleable, ductile and good conductors of heat and electricity • Non-Metals: tend to not share the properties of metals and are usually gases or brittle solids at room temperature • Metals and non metals vary in their reactivity

  36. A TOUR OF THE COMMON ELEMENTS • Turn to page 45-47 • There are 8 common elements-4 are metals and 4 are non-metals • Use the handout provided to summarize these 8 common elements in your own words

  37. THE PERIODIC TABLE • The Periodic Table Overview • Organizes the elements into their properties • Listed in rows according to increasing atomic number • Rows are arranged to elements with similar properties line up in vertical columns • Rows  called periods • Columns  called families or groups • 2 families of metals • Alkali metals • Alkaline earth metals • 2 families of non metals • Halogens • Noble gases

  38. DIMITRI MENDELEEV • A Russian teacher and chemist who was the first person to organize the elements into what has becomes today’s periodic table

  39. THE PERIODIC TABLE • Atomic Number: number of protons in the nucleus of an element • Atomic Mass (weight): mass of the average atom (units are atomic mass unit) • Ion charge: when an atom gains or losses electrons and electric charge forms on the atom called the ion charge • Some atoms have more than one ion charge

  40. GETTING TO KNOW THE PERIODIC TABLE • Use the handout of the Blank Periodic Table of Elements and Page 54 of your textbook • Use the information of page 54 to make your own periodic table • Use pencil crayon to color the metals, metalloids and non-metals • Be sure to include the element name, element symbol, atomic number, ion charge and atomic mass  we will learn what these are tomorrow

  41. LESSON 5: THE PERIODIC TABLE Science 9

  42. Think-Pair-Share • Brainstorm with a partner what you know about the Periodic Table • What is it? • Why do we have it? • What kinds of things does it tell us?

  43. THE PERIODIC TABLE • The Periodic Table Overview • Organizes the elements into their properties • Listed in rows according to increasing atomic number • Rows are arranged to elements with similar properties line up in vertical columns • Rows  called periods • Columns  called families or groups • 2 families of metals • Alkali metals • Alkaline earth metals • 2 families of non metals • Halogens • Noble gases

  44. DIMITRI MENDELEEV • A Russian teacher and chemist who was the first person to organize the elements into what has becomes today’s periodic table

  45. THE PERIODIC TABLE • Atomic Number: number of protons in the nucleus of an element • Atomic Mass (weight): mass of the average atom (units are atomic mass unit) • Ion charge: when an atom gains or losses electrons and electric charge forms on the atom called the ion charge • Some atoms have more than one ion charge

  46. METALS, NON METALS, METALLOIDS • Mendeleev arranged the elements according to their properties • He noticed that 3 main groups existed: metals, non metals, metalloids

  47. PERIODS AND FAMILIES • Period • Horizontal row = period • There are 7 rows on the periodic table • Family • Vertical row = family • There are 18 columns on the periodic table • Families share similar physical and chemical properties • 4 families: alkali metals, alkaline earth metals, halogens, noble gases

  48. ALKALI METALS(GROUP 1 EXCLUDING HYDROGEN) • Li, Na, Rb, Cs, Fr • Highly reactive • React with water and oxygen • Reactivity increases as you go down the table • Low melting points • Soft, can be cut with a knife

  49. ALKALINE EARTH METALS(GROUP 2) • Be, Mg, Ca, Sr, Ba, Ra • Less reactive than alkali metals but will burn in air if heated • Used in fireworks • Example: red fireworks caused by strontium • React with water but not as much as alkali metals

  50. HALOGENS (GROUP 17) • F, CL, Br, I, At • Non-metals • Highly reactive • Fluorine and chlorine are gases at RT • Bromine is a liquid • Iodine is a solid • Fluorine is the most reactive and iodine is the least

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