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CHEMISTRY!!!!

CHEMISTRY!!!!. Subatomic particles. Actual mass (g). Relative mass. Name. Symbol. Charge. Electron. e -. -1. 1/1840. 9.11 x 10 -28. Proton. p +. +1. 1. 1.67 x 10 -24. Neutron. n 0. 0. 1. 1.67 x 10 -24. Counting the Pieces.

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CHEMISTRY!!!!

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  1. CHEMISTRY!!!!

  2. Subatomic particles Actual mass (g) Relative mass Name Symbol Charge Electron e- -1 1/1840 9.11 x 10-28 Proton p+ +1 1 1.67 x 10-24 Neutron n0 0 1 1.67 x 10-24

  3. Counting the Pieces • Atomic Number = number of protons in the nucleus • # of protons determines kind of atom • The same as the number of electrons in the neutral atom. • Mass Number = the number of protons + neutrons. • These account for most of mass

  4. Counting the Pieces • Protons: equal to atomic number • Neutrons: Mass Number – Atomic Number • Electrons: In a neutral atom equal to atomic number

  5. Symbols • Contain the symbol of the element, the mass number and the atomic number.

  6. Symbols • Contain the symbol of the element, the mass number and the atomic number. Mass number X Atomic number

  7. Symbols • Find the • number of protons • number of neutrons • number of electrons • Atomic number • Mass Number 19 F 9

  8. Symbols • Find the • number of protons • number of neutrons • number of electrons • Atomic number • Mass Number 80 Br 35

  9. Symbols • if an element has an atomic number of 34 and a mass number of 78 what is the • number of protons • number of neutrons • number of electrons • Complete symbol

  10. Symbols • if an element has 91 protons and 140 neutrons what is the • Atomic number • Mass number • number of electrons • Complete symbol

  11. What if Atoms Aren’t Neutral • Ions: charged atoms resulting from the loss or gain of electrons

  12. What if Atoms Aren’t Neutral • Anion: negatively charged ion; result from gaining electrons • Take the number of electrons in a neutral atom and add the absolute value of the charge Identify: Number of Protons Number of Neutrons Number of Electrons 81 1- Br 35

  13. What if Atoms Aren’t Neutral • Cation: positively charged ion; result from the loss of electrons • Take the number of electrons in a neutral atom and subtract the value of the charge Identify: Number of Protons Number of Neutrons Number of Electrons 27 Al 3+ 13

  14. Isotopes • Atoms of the same element can have different numbers of neutrons • Different mass numbers • Called isotopes

  15. Naming Isotopes • We can also put the mass number after the name of the element. • carbon- 12 • carbon -14 • uranium-235

  16. Atomic Mass • How heavy is an atom of oxygen? • There are different kinds of oxygen atoms • We are more concerned with average atomic mass • Average atomic mass is based on abundance of each element in nature. • We don’t use grams because the numbers would be too small

  17. Measuring Atomic Mass • Unit is the Atomic Mass Unit (amu) • It is one twelfth the mass of a carbon-12 atom • Each isotope has its own atomic mass, thus we determine the average from percent abundance

  18. Atomic Mass • Is not a whole number because it is an average. • are the decimal numbers on the periodic table.

  19. Modern Periodic Table • The modern periodic table consists of Rows and Columns • Rows - • Horizontal • Also known as Periods • Numbered 1-7 • Columns - • Vertical • Also known as Groups and Families • Numbered 1-18

  20. Metals • The most common class of elements is Metals • Metals become cations • What is a cation? How are they formed? • Positively charged atom - Lose electrons • Metals are generally solid (except Hg), conductive of heat and electricity, malleable, ductile, and shiny

  21. Alkali Metals • Group 1 elements are known as Alkali Metals • Alkali metals include Li, Na, K, Rb, Cs, Fr • Alkali metals are generally dull, soft, and reactive – rarely found as free elements

  22. Alkaline Earth Metals • Group 2 elements are known as Alkaline Earth Metals • Alkaline earth metals include Be, Mg, Ca, Sr, Ba, and Ra • Alkaline earth metals are harder, denser, and stronger than alkali metals • Less reactive than alkali metals, but still rarely found as free elements

  23. Transition Metals • Elements in groups 3-12 (3B-2B) are known as Transition Metals • Transition metals include Mn, Fe, Ag, Au, Mo, etc. • Lanthanide and Actinide Series elements fill in the f orbitals – known as inner transition elements

  24. Metalloids • Elements that border the staircase on the periodic table are known as Metalloids • Metalloids include: B, Si, Ge, As, Sb, Te, Po, At • Metalloids have properties of both metals and nonmetals

  25. Nonmetals • Nonmetals are found to the right of the staircase on the periodic table • Nonmetals generally become anions • What is an Anion? How are they formed? • Negatively charged atom - Gain electrons • Nonmetals are often gases or dull, brittle solids • Nonmetals generally show poor conductivity, ductility, and malleability

  26. Halogens • Group 17 elements are known as Halogens • Halogens include F, Cl, Br, and I • Halogens are the most reactive nonmetals – often found in compounds

  27. Noble Gases • Elements in group 18 are known as Noble Gases • Noble Gases include He, Ne, Ar, Kr, Xe, Rn • Noble gases are extremely unreactive

  28. Legend

  29. Pure Substances • Cannot be physically separated • Every sample has the same characteristics and they can be used to identify a substance

  30. Elements • Are made up of ONE type of atom • Atoms are the smallest unit of an element that maintains the chemical identity of that element • They can be found on the Periodic Table • Examples: Carbon, Nitrogen, Calcium

  31. Compounds • Can be broken down into simple stable substances • Are made up of two or more types of atoms that are chemically bonded • Examples: Water (H2O), sugar (C12H22O11)

  32. Mixtures • A blend of two or more kinds of matter, each which retains its own identity and properties

  33. Homogeneous Mixtures • Have uniform composition • Also known as SOLUTIONS • Examples: salt water, tea

  34. Solutions • ALLOYS are solid solutions that contain at least 1 metal • They are blended together so that they have more desirable properties • Some alloys you may know are: • Stainless Steel: iron, chromium, and zinc • Brass: zinc and copper • Bronze: tin and copper • Sterling Silver: copper and silver

  35. Heterogeneous Mixtures • Do not have uniform composition • You can see the particles in them • Examples: • Sand on the beach (contains sand, shells, rocks, bugs, etc) • Soil (contains dirt, rocks, worms, etc) • Chicken Soup (contains water, chicken, veggies etc)

  36. Suspensions • A heterogeneous mixture where the solid particles eventually settle out of solution • Examples: • Muddy water • Mixtures of two solids • Paint

  37. Properties of Matter • All pure substances have characteristic properties • Properties are used to distinguish between substances • Properties are also used to separate substances

  38. Physical Properties • A Physical Property is a characteristic that can be observed or measured without changing the composition of the substance • Physical properties describe the substance itself • Examples • Physical State • Color • Mass, shape, length • Magnetic properties

  39. Chemical Properties • A Chemical Propertyindicates how a substance will react with another • Chemical properties cannot be determined without changing the identity of the substance • Examples: • Iron Rusting • Silver Tarnishing

  40. Physical Changes • A Physical Change is a change in a substance that does not alter the substance’s identity • Examples: • Grinding • Cutting • Melting • Boiling

  41. Chemical Changes • A change in which one or more substances are converted into different substances is called a Chemical Change • Signs of a Chemical Change: • Color Change • Gas is Released • Temperature Change • Precipitate – Solid falls out of solution • Substance Disappears

  42. Electrons • Electrons fill in an atom in energy levels • Electrons occupy the LOWEST available energy level • Energy Levels hold limited amounts of electrons • 1st Level – 2 electrons • 2nd Level – 8 electrons • 3rd Level – 18 electrons • 4th Level – 32 electrons

  43. Chlorine (Cl) P = 17 N = 18 E = 17

  44. Nitrogen (N) P = 7 N = 7 E = 7

  45. Aluminum (Al) P = 13 N = 14 E = 13

  46. Valence Electrons • Electrons in outermost shell that determine chemical behavior • Maximum of 8 valence electrons • Atoms with same valence electrons will act similarly • Group 1 elements? • 1 valence electron • Group 17 elements? • 7 valence electrons

  47. How Atoms Combine • Two or more atoms that are chemically combined make up a compound • The combination results in a chemical bond, a force which holds elements together in a compound

  48. Covalent Bonds • Covalent Bonds are formed when atoms in a compound share electrons • Molecule – two or more atoms held together by a covalent bond • Usually occurs between nonmetals

  49. Covalent Bonding in Water

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