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The Atom. Essential Question? Compare and contrast the characteristics of an atom and function of these characteristics in an atom?

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Presentation on theme: "The Atom. Essential Question? Compare and contrast the characteristics of an atom and function of these characteristics in an atom?"— Presentation transcript:

1 The Atom

2 Essential Question? Compare and contrast the characteristics of an atom and function of these characteristics in an atom?

3 Structure of an Atom Atom Proton (p + ) Neutron (n o ) Electron (e - )

4 Proton p + Positive Charge (p + ) Located in the nucleus Mass of a proton = x g Relative Mass 1 amu Function: Gives an atom its identity – If the # of protons changes so does the type of atom Ex: Hydrogen has 1 proton Helium has 2 protons Lithium has 3 protons The Atomic # always equals the # of protons Ex: Hydrogen has an Atomic # = 1 and has 1 proton Proton

5 Neutron n o No charge Located in the nucleus Mass of a neutron x g Relative Mass = 1 amu Function: Adds mass to nucleus Mass # - Atomic # = # of n o Ex: 1-1=0 hydrogen has 0 n o Neutron

6 Electron e- Negative charge Has very small mass (9.109 x g) and is not included in the atomic mass of the atom Relative Mass = 1/1840 Located outside the nucleus - electron cloud - orbitals - shells - energy levels Ex: Hydrogen has 1e - Function: Is responsible for an atoms behavior Electron

7 Atomic # = # protons = # electrons –Which element has 32 protons? Symbol__ Name __ –Which element has 14 protons? Symbol__ Name __ The mass number is the number of protons PLUS the number of neutrons in an atom. This is because the mass of the atom is mainly inside the nucleus where the protons and neutrons are found. The mass number – protons = number of neutrons on the Periodic Table

8 Find and Round the Atomic Mass to the nearest whole number ElementSymbolAverage Atomic Mass Mass Number (round # up or down) Ca Barium Cl Nickel

9 Find and Round the Atomic Mass to the nearest whole number ElementSymbolAverage Atomic Mass Mass Number (round # up or down) CalciumCa40.1 amu40 amu BariumBa137.3 amu137 amu ChlorineCl35.5 amu36 amu NickelNi58.7 amu59 amu

10 Three types of atoms Atoms can be an ElementIonIsotope

11 This will help you determine which type of atom you have If the p + e - then you have an ION If you add the p + + n o & the mass # the mass on the PT, you have an ISOTOPE If the mass # = the mass # on the PT, and the p + = e - then you have an Element

12 Element Cannot be broken down into simpler substances by physical or chemical means Each has a symbol located on the Periodic Table Ex:Ag – Silver, Pb – Lead Each has an atomic # and atomic mass Ex:Ag –Atomic # = 47 Atomic mass = amu Pb – Atomic # = 82 Atomic mass = amu Atomic # = # of p + = # of e - If the # of p + = the # of e - the atom is electrically neutral Atomic mass = # of p + + # of n o (this number must match the rounded atomic mass (or Mass #) on the periodic table)

13 Element - Fill in the table below ElementAtomic #ProtonsNeutronsElectronsMass # H He Li Be B C N O F Ne

14 Element Fill in the table below ElementAtomic #ProtonsNeutronsElectronsMass # H11011 He22224 Li33437 Be44549 B C N O F Ne10 20

15 Ion An ion is an atom with a charge. The charge is either positive or negative The charge depends on if the electrons are donated (lost) or accepted (gained) Ex: If an atom donates e - then the charge becomes positive (+) Na + Ex: If an atom accepts e - then the charge becomes negative (-) Cl - To identify an ion the # of protons will NOT equal the # of electrons Ex:Cl normally has 17e - A Cl - ion has 18e - (Cl has accepted 1e - )

16 Ion - Fill in the table below ElementProtonsElectronsGained or Lost e -? H0 Li2 Be2 B2 N8 O9 F10

17 Ion - Fill in the table below ElementProtonsElectronsGained or Lost e -? H10Lost Li32Lost Be42Lost B52 N78Gained O89 F910Gained Are the number of protons and electrons the same or different? DIFFERENT

18 Isotopes Are atoms with the same number of protons but has a different number of neutrons than the normal number of neutrons in an atom To calculate the # of n o round the atomic mass to the nearest whole number then subtract the atomic number. When the atomic mass is rounded it is called the Mass number Mass number – Atomic number = # of n o Ex: (Pb) 207 – 82 = 125 neutrons If the atom is an isotope then there will be more neutrons and the mass will be more Ex: (Pb) 208 – 82 = 126 neutrons Isotopes are neutron rich and unstable

19 Isotopic Notation Ex: Silicon Si Mass # Atomic # Isotopic Name Silicon-28 Mass #

20 Lets Compare the Following Carbon-12Carbon-13Carbon-14 Atomic # Protons Electrons Mass Number Neutrons

21 Lets Compare the Following Carbon-12Carbon-13Carbon-14 Atomic #666 Protons666 Electrons666 Mass Number Neutrons678 How are the notations alike? How are the above notations different? Same protons and electrons Different Mass # & neutrons

22 Review Isotopes are atoms of the same element with the same number of _______, but with different numbers of _______. Answer questions 1-5 in Part I Answer questions 6-10 in Part II

23 Complete Isotopes or Different Elements WS Front and back #StatementElement(s)Different Element, Isotope 1Element D has 6 protons and 6 neutrons Element F has 7 protons and 7 neutrons 2Element J has 27 protons and 32 neutrons Element L has 27 protons and 33 neutrons 3Element X has 17 protons and 18 neutrons Element Y has 18 protons and 17 neutrons 4Element Q has 56 protons and 81 neutrons Element R has 56 protons and 82 neutrons 5Element T has an atomic # of 20 and an atomic mass of 40 Element Z has an atomic # of 20 and an atomic mass of 41 6Element W has 8 protons and 8 neutrons Element V has 7 protons and 8 neutrons 7Element P has an atomic # of 92 and an atomic mass of 238 Element S has an atomic # of 92 and an 143 neutrons

24 Complete Isotopes or Different Elements WS Front and back #StatementElement(s)Different Element, Isotope 1Element D has 6 protons and 6 neutrons Element F has 7 protons and 7 neutrons Carbon Nitrogen DE 2Element J has 27 protons and 32 neutrons Element L has 27 protons and 33 neutrons Cobalt - 59 Cobalt - 60 Isotope 3Element X has 17 protons and 18 neutrons Element Y has 18 protons and 22 neutrons Chlorine Argone DE 4Element Q has 56 protons and 81 neutrons Element R has 56 protons and 82 neutrons Barium Barium Isotope 5Element T has an atomic # of 20 and an atomic mass of 40 Element Z has an atomic # of 20 and an atomic mass of 41 Calcium - 40 Calcium - 41 Isotope 6Element W has 8 protons and 8 neutrons Element V has 7 protons and 7 neutrons Oxygen Nitrogen DE 7Element P has an atomic # of 92 and an atomic mass of 238 Element S has an atomic # of 92 and an 143 neutrons Uranium Uranium Isotope

25 ElementSymbolAtomic #Mass ## of p + # of n o # of e - Helium Br 13 U 1112 Krypton Ca Ag61 Fill in the Chart Below

26 ElementSymbolAtomic #Mass ## of p + # of n o # of e - HeliumHe24222 MagnesiumMg ZincZn BromineBr AluminumAl UraniumU SodiumNa KryptonKr CalciumCa SilverAg Fill in the Chart Below

27 Summarize Fill in Part V chart

28 Isotopic Notation Isotopic Name Atomic ## of p + # of n o # of e - Mass # Zinc Lead Thallium-210 Fill in the Chart Below

29 Isotopic Notation Isotopic Name Atomic ## of p + # of n o # of e - Mass # Tungsten Fill in the Chart Below

30 Isotopic Notation Isotopic Name Atomic ## of p + # of n o # of e - Mass # Bromine Zinc Chlorine Lead Einsteinium Plutonium Fermium Thallium Fill in the Chart Below

31 Isotopic Notation Isotopic Name Atomic ## of p + # of n o # of e - Mass # Mercury Francium Platinum Tungsten Gold Fill in the Chart Below

32 Summarize Answer questions part VI

33 Part VII Potassium K – 39 has 20 neutrons K – 40 has 21 neutrons K – 41 has 22 neutrons

34 Atomic Mass Determination Chemist have developed a method of measuring mass of an atom called: Atomic Mass Determination Unit is abbreviated amu They did this because the masses of subatomic particles are so small that even scientific notation makes it hard to calculate the masses of elements. The atomic mass that you see on the PT is the average mass for the isotopes of that element. The atomic mass you see on the PT is also the isotope that is most abundant in nature!!! Answer Question 1 & 2

35 How is Atomic Mass Calculated? The mass on the Periodic Table is the average mass of the isotopes of an atom To determine the atomic mass of an atom use this formula (Mass (amu) x Percent abundance)= Isotope A (Mass (amu) x Percent abundance)= Isotope B Add A + B / 100 = atomic mass

36 Example Problem #1 Calculate the atomic mass of the unknown element. Then identify the element using the Periodic Table? Isotope Isotopic Notation Mass (amu)Percent Abundance 185 X X

37 ( amu x 37.40) = amu ( amu x 62.60) = amu amu trace/least abundant amu most abundant / 100 = amu Rhenium = Re

38 Practice Problem #2 Calculate the atomic mass of the unknown element. Then identify the element? Isotope Isotopic Notation Mass (amu)Percent Abundance 113 X __?__ 115 X Which Isotope is trace and which is more abundant?

39 ( amu x 4.30 ) = 485 amu ( amu x 95.70) = amu 485 amu trace/least abundant amu most abundant / 100 = amu Indium = In

40 Practice Problems (Book) Pp #15 Boron has 2 naturally occurring isotopes: boron-10(abundance = 19.8%, mass = amu), boron-11 (abundance = 80.2 %, mass = amu) Calculate the atomic mass of boron. #16 Helium has 2 naturally occurring isotopes, helium-3 and helium-4. The atomic mass of helium is amu. Which isotope is more abundant in nature? Explain #17 Calculate the atomic mass of magnesium. The three magnesium isotopes have atomic masses and relative abundances of amu (78.99%), amu (10.00%), amu (11.01%).

41 Practice Problem #1 Answer = amu Isotope Isotopic notation Mass (amu)Percent Abundance 10 B B

42 Practice Problem #2 Answer = amu Isotope Isotopic Notation Mass (amu)Percent Abundance 107 Ag Ag

43 Practice Problem #3 Answer = amu Isotope Isotopic Notation Mass (amu)Percent Abundance 24 Mg Mg Mg

44 Practice Problem #4 Helium-4 is most abundant b/c its mass is closer to the average atomic mass on the PT Helium-3 mass is not as close as Helium-4, so Helium-3 is less abundant

45 Practice Problem #5 Answer = amu Isotope Isotopic Notation Mass (amu)Percent Abundance 20 Ne Ne

46 Practice Problem #6 Answer = amu Isotope Isotopic Notation Mass (amu)Percent Abundance 176 Hf Hf Hf Hf Hf

47 Practice Problem #7 Answer = amu Isotope Isotopic Notation Mass (amu)Percent Abundance 28 Si Si Si

48 Practice Problem #8 Answer = amu Isotope Isotopic Notation Mass (amu)Percent Abundance 107 Ag Ag

49 Practice Problem #9 Answer = Neon-20 Why? Its mass is closest to the average mass of neon on the PT. Isotope Isotopic Name Atomic #Mass (amu) Neon Neon Neon

50 Practice Problem #10 Answer = amu Isotope Isotopic Notation Mass (amu)Percent Abundance 78 Kr Kr Kr Kr Kr Kr

51 How was the Atom Discovered? Fill in Atomic Theory WS Use your book Many early philosophers thought matter was made up of 4 components Earth – Air, Fire – Water

52 Democrituss Ideas ( B.C.) Matter is composed of empty space through which atoms move Atoms are solid homogenous, indestructible & indivisible Different kinds of atoms have different sizes & shapes The differing properties of matter are due to the size, shape and movement of atoms Apparent changes in matter result from changes in the grouping of atoms and not from the changes in atoms themselves

53 Daltons Ideas ( ) All matter is composed of extremely small particles called atoms All atoms of a given element are identical, having the same size, mass and chemical properties. Atoms of a specific element are different than those of any other element. Atoms cannot be created, divided into smaller particles or destroyed. Different atoms combine in simple whole ratios to form compounds In a chemical reaction, atoms are separated, combined or rearanged.

54 Mendeleevs Contribution Developed the Periodic Table Arranged the Periodic Table based on atomic mass

55 Roentgens Discovery X-Rays – invisible rays of e - bombarding the surface of materials Noticed this mysterious radiation passed through soft tissue, but not bone or metals

56 Curries Discovery Radioactivity – radiation Found Polonium, Radium

57 Bacquerels Contribution Phosphorescent minerals – uranium salts exposed photographic plates in dark Found that uranium naturally emits radiation

58 J. J. Thomsons Discovery Determine the mass ratio of particles Said Dalton was wrong Found e -

59 Thompsons Concept of the Atom Plum Pudding Model Negatively charged electrons were distributed throughout a uniform positive charge

60 Cathode Ray Experiment William Crookes – Accidentally found Lead to the invention of the TV, Computer monitors (Radiation hits light producing chemicals on the backsides of screens) Vacuum tube – low pressure – Electric charge (-) cathode passes to (+) anode – light is electrons React to magnets Light is a stream of charged particles Particles have a (-) charge Found a particle smaller than the H atom by looking at known charge to mass ratios. WS – Cathode Ray Experiments

61 Rutherfords Contribution ( ) Found Nucleus Nucleus has a (+) charge Devised a way with H. G. Moseley to bombard elements with a cathode ray which they used to assign atomic numbers to elements Found - Alpha, Beta, Gamma radiation

62 Rutherfords Gold Foil Experiment Narrow beam of alpha particles was a thin sheet of gold foil. Zinc sulfide screen surrounding the gold foil produced a flash of light whenever it was struck by an alpha particle

63 WS – Understanding Rutherfords Gold Foil Experiment The deflection was the alpha particle bouncing off the nucleus

64 Bohrs Contribution ( ) Model of an atom Small orbit = lower energy state or energy level Part of the Manhattan Project Advocate for safe use of Atomic energy

65 Chadwicks Discovery Neutron No Charge Mass almost = to mass of proton

66 Definitions Atomic Mass – total average mass of an atom Atomic number - # of p +, in an atom Mass Number – total # of p +, & n o Atom – Smallest particle in an element, electrically neutral, spherically shaped and composed of p +, n o and e - Ion – An atom or bonded group of atoms w/ a (+) or (-) charge. Isotope – atoms of the same element w/ different # of n o

67 ElementSymbol Element, Ion, Isotope Atomic #Mass #Protonsneutronselectrons B Sulfur 7 Chlorine18 Carbon Iodine Complete the Following Table

68 ElementSymbol Element, Ion, Isotope Atomic #Mass #Protonsneutronselectrons BoronBE SulfurSE NitrogenNE ChlorineClIon Carbon-14C-14Isot PhosphorusPE AluminumAlIsot Iodine-128I-128Iso ArgonArE Complete the Following Table


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