# Atomic Structure  Define the atom  Structure of the Nuclear Atom  Distinguish between atoms.

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Atomic Structure  Define the atom  Structure of the Nuclear Atom  Distinguish between atoms

 In groups of 7 you will research the following scientists’ ideas and contributions to the atomic model.  1. John Dalton, 2. Democritus, 3. J.J Thomson, 4. Ernest Rutherford, 5. Robert Millikan, 6. Eugen Goldstein, 7. James Chadwick 6. Eugen Goldstein, 7. James Chadwick  You will present your findings to the class Early Models of the Atom

Subatomic particle chargesymbollocationMass (mass of proton=1) What are the 3 kinds of subatomic particles? ? Charge ? Location ? Symbol protons neutrons electrons

 The Number of protons (atomic number)  Atoms are electrically neutral; therefore the number of protons (+) must equal the number of electrons (-) What makes one element differ from another? elementAtomic #protonselectrons K 19 5 S 16 Try these! 6 23 V 50.941 23 V 50.941 symbol Average Atomic mass Atomic number

 Find the difference between the mass number and atomic number How do you find the # of neutrons? 14 Si 28.086 ? Atomic number # of protons # of electrons ? Average atomic mass Round this for mass number Atomic number = Mass number = Number of neutrons=

1.Write the symbol, place the atomic number as the subscript and the mass number as the superscript to the left of the symbol. Shorthand notation 14 Si 28.086 28 14 Si 2.Also can be written with the name of the symbol and the mass number Silicon-28

elementAtomic #Mass #protonselectronsneutrons Beryllium49 Neon1020 Sodium1123practice A. B.How many neutrons are in each atom? 16 8 O 32 16 S 108 47 Ag p+ = e- = n 0 = p+ = e- = n o = p+ = e- = n o =

elementAtomic #Mass #protonselectronsneutrons Radon86???136 Iodine?? 53?74 ?? 128? 52? bismuth?? 83?126 Remember!! Atomic # = protons = electrons Mass # = Protons + Neutrons Neutrons = Mass # - Protons Protons = Mass # - Neutrons Tellurium

Atoms that have the same number of protons, but different numbers of neutrons, therefore having different mass numbers Atoms that have the same number of protons, but different numbers of neutrons, therefore having different mass numbers Isotopes are chemically alike due to the # of protons and electrons Isotopes are chemically alike due to the # of protons and electronsIsotopes There are 3 known isotopes of hydrogen. Each isotope has one proton Most common = hydrogen-1 or H 2 nd isotope has one neutron (mass # of 2) = _____________or hydrogen-2 or H 3 rd isotope has 2 neutrons (mass # of 3) = ___________or hydrogen-3 or H 1111 2121 3131

1. Three isotopes of oxygen are oxygen-16, oxygen-17, oxygen-18. Write the symbol for each, including the atomic number and mass number. 1. Three isotopes of chromium are chromium- 50, chromium-52, and chromium-53. How many neutrons are in each isotope, given that chromium has an atomic number of 24? Practice 16 8 O 17 8 O 18 8 O Chromium-50 = ____ neutrons Chromium-52 = ____neutrons Chromium-53 = ____ neutrons

1. Research common isotopes (radioistopes) 2. Create a display over commonly used isotopes. 3. Include the isotope and its use 4. Also may include pictures, etc. Extra Credit

 Atomic mass unit- (amu)-  Atomic mass= Atomic Mass Calculating the atomic mass Multiply the mass of each isotope by the natural abundance, expressed as a decimal, and then add the products

Element X has 2 natural isotopes. The isotope with a mass of 10.012 amu ( 10 X) has a relative abundance of 19.91%. The isotope with a mass of 11.009 amu ( 11 X) has a relative abundance of 80.09%. Calculate the atomic mass of this element  knowns * isotope 10X mass = 10.012 amu mass = 10.012 amu rel. abun= 19.91% or 0.1991 rel. abun= 19.91% or 0.1991 *Isotope 11 X: mass = 11.009 amu mass = 11.009 amu rel. abun.= 80.09% or 0.8009 rel. abun.= 80.09% or 0.8009  unknowns * Atomic mass of element X ? Practice Calculate For 10 X: 10.012 amu x 0.01991= 1.993 amu For 11 X: 11.009 amu x 0.8009 = 8.817 amu For element X: atomic mass =10.810 amu

1. The element of copper has naturally occurring isotopes with mass number of 63and 65. The relative abundance and atomic masses are 69.2% for mass = 62.93 amu, and 30.8% for mass = 64.93 amu. Calculate the average atomic mass of copper 2. Calculate the atomic mass of bromine. The 2 isotopes of bromine have atomic masses and relative abundance of 78.92 amu (50.69%) and 80.92 amu (49.31%) Practice

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