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Chapter 4: Atoms & Elements Elements & Symbols The Periodic Table Atomic Structure Isotopes Electron Energy Levels CH110 2-1 Atomic Symbols Nitrogen Hydrogen Nickel Aluminum Bromine Each element is assigned a unique symbol 1-2 letters; 1st is capitalized CH110 2-2 Sodium (Natrium) Atomic Symbols Potassium (Kalium) Silver (Argentum) Iron (Ferrum) Gold (Aurum) Lead (Plumbum) The original name is often of Latin or Greek origin CH110 2-3 Atomic Symbols Carbon Calcium Chromium Cobalt Copper (Cu) Chlorine Elements with same starting letter, get second letter added to the symbol CH110 2-5 Periodic Table: Groups Alkali Metals Alkaline Earth Metals IA H Noble gases II A Transition Metals Na Mg III B IVB V B VIB VIIB Ca Sc Ti Rb Sr VIIIA III A IV A V A VI A VIIA Li Be K Halogens Y V VIII B IIB B C N O F Ne Al Si P S Cl Ar Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te Cs Ba Ls Hf Ta W Re Os Ir Fr Ra Ac IB He I Xe Pt Au Hg Tl Pb Bi Po At Rn Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu AmCm Bk Cf Es Fm Md No Lr CH110 3 - 162 - 6 Periodic Table: Periods Periods are assigned numbers 1 H 2 Li Be B C N O F 3 Na Mg Al Si P S Cl Ar 4 K 5 Rb Sr 6 Cs Ba Ls Hf Ta W Re Os Ir 7 Fr Ra Ac Ca Sc Ti Y V He Ne Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Pt Au Hg Tl Pb Bi Po At Rn Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr CH110 3 - 152 - 7 Metals Lustrous, malleable and ductile. Conductors (heat & electricity) H Solids at room temp (except Hg) He Li Be Lose electrons to non-metals. B C N O F Ne Na Mg K Al Ca Sc Ti Rb Sr Y V P S Cl Ar Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te Cs Ba Ls Hf Ta W Re Os Ir Fr Ra Ac Si I Xe Pt Au Hg Tl Pb Bi Po At Rn Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr CH110 2-8 Non-metals H He Li Be B C N O F Na Mg Al Si P S Cl Ar K Ga Ge As Se Br Kr Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Gas, liquid, solid (dull, brittle) Zr Nb Mo Tc Ru Rh Pd Ag Cd Poor Yconductors = Insulators Rb Sr In Sn Sb Te Cs Ba Ls Hf Ta W Re Os Ir Pt Au Hg Many are diatomic molecules. Tl Pb Bi Po At Rn Pr Nd Pm Sm Eu Gd Tb Gain e’s from Ce metals Dy Ho Er Tm Yb Lu Fr Ra Ac I Ne Xe Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Share e’s with other non-metals CH110 2-9 Metaloids H He Li Be B C N O F Na Mg Al Si P S Cl Ar K Ca Sc Ti Rb Sr Y V Ne Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te Intermediate properties Cs Ba Ls Hf Ta W Re Os Ir I Xe Pt Au Hg Tl Pb Bi Po At Rn Semi conductors Fr Ra Ac Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr CH110 2 - 10 Metals Non-metals Metaloids H He Li Be B C N O F Na Mg Al Si P S Cl Ar K Ca Sc Ti Rb Sr Y V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te Cs Ba Ls Hf Ta W Re Os Ir Fr Ra Ac Ne I Xe Pt Au Hg Tl Pb Bi Po At Rn Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr CH110 2 - 11 A model of matter Atom - The smallest unit of an element that is still that element. ie. Aluminum (Al) Molecule -The smallest unit of a pure substance that is still that substance. May contain > 1 atom or element. ie. Water (H2O) CH110 2 - 12 Structure of the atom Nucleus = Small, dense, + charge in the center of an atom. contains protons & + + + + + + neutrons CH110 2 - 13 Structure of the atom Nucleus Electrons - charged particles that surround the nucleus. Electrons move around nucleus in orbitals. CH110 2 - 14 Structure of the atom The nucleus is a small part of an atom. If the nucleus was the size of a marble, the atom would fill a football stadium. The nucleus would weigh over 10,000 tons. CH110 2 - 15 The atomic symbol A = Atomic mass (amu) = # protons + # neutrons A Z - X Z = Atomic number + - = # protons = # electrons CH110 - + + - + + + 2 - 16 The atomic symbol A = Atomic mass = # protons + # neutrons 6 6 - 12 6 X Z = Atomic number + - = # protons = # electrons CH110 - + + - + + + 2 - 17 The atomic symbol A = Atomic mass = # protons + # neutrons 12 6 C Z = Atomic number + - = # protons = # electrons CH110 - + + - + + + 2 - 18 The atomic symbol A = Atomic mass = p + n = 23 23 Na 11 Z = Atomic # = p = 11 Sodium CH110 2 - 19 Why is the atomic weight on the tables not a whole #? 47 Silver Ag 107.87 Atomic number Name of the element Elemental Symbol Atomic mass (weight) Atomic weight = The average, relative mass of an atom in an element. Isotopes of Hydrogen Isotopes = Atoms of the same element but having different masses. 1 2 3 H H H 1 1 1 + Protium 99.99% CH110 - + Deuterium 0.01% + Tritium Trace % 2 - 21 Isotopes of Hydrogen Isotopes = Atoms of the same element but having different masses. 1 2 3 H H H 1 1 1 + - + + Average Atomic weight of Hydrogen = 1.00794 amu CH110 2 - 22 Isotopes of Carbon 12 C 6 - - + + 13 C 6 - - - + + + + + - 98.89% - + + + + - - + 14 C 6 - - 1.11% + - - + - + + + + - - Trace % Average Atomic weight of C= 12.011 amu CH110 2 - 23 Radioactive Isotopes 14 C 6 3 H 1 - - + + Nucleus is unstable So falls apart (decays) Giving radioactive particles CH110 - + - + + + + - - 2 - 24 The atomic symbol & isotopes Determine the number of protons, neutrons and electrons in each of the following. 31 15 P CH110 138 56 Ba 238 92 U 2 - 25 Atomic Structure CH110 Symbol At# Mass ____ Be ____ 4 ____ 9 Cl ____ 17 37 Si ____ 14 ____ 28 P N 4 5 e- ___ 4 ___ 17 ___ 20 ___ 17 ___ 14 14 14 ___ 2 - 26 Electron arrangement 24 Mg 12 Electrons fill layers around nucleus 32 Low High 18 A new layer is 8 added for each 2 row or period in the table. Shells = Energy levels CH110 2 - 27 IA IIA 1 H 1 7 Li 3 CH110 4 He 2 9 Be 4 2 - 28 IA IIA IIIA 1 H 1 7 Li 3 CH110 9 Be 4 11 5B 2 - 29 IIIA 11 5B CH110 IVA 12 6C VA 13 7N 2 - 30 IA IIA 1 H 1 7 Li 3 23 Na 11 CH110 VIIIA 4 He 2 9 Be 4 20 10Ne 24 12Mg 40 18Ar 2 - 31 1 H 1 7 Li 3 23 Na 11 1 9 Be 4 24 12Mg Valence electrons Where most chemical Reactions occur. 2 3 11 5B 27 13Al Inner electrons: No rxns if normal conditions. CH110 2 - 32 Inner vs. valence electrons Valence electrons This is where most chemical reactions occur. Inner electrons Not much happens here under normal conditions. With added energy inner electrons jump to higher levels, then fall back giving E CH110 2 - 33 1 8 1 H 1 7 Li 3 23 Na 11 CH110 2 4 He 2 9 Be 4 20 10Ne 24 12Mg 40 18Ar 2 - 34 1 H 1 7 Li 3 23 Na 11 Electron dot (Lewis) Structures H Li Show only Valence Electrons Na K CH110 2 - 35