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Exploring Elements: Symbols, Bonds & Isotopes

Dive into the world of chemical elements, symbols, and their unique properties. Learn about isotopes, electron configurations, and the Periodic Table, all through interactive practice and engaging resources. Unveil the secrets of molecules, orbitals, and atomic structures in this educational journey. Discover the significance of valence electrons, bonding, and atomic mass in the fascinating realm of chemistry.

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Exploring Elements: Symbols, Bonds & Isotopes

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  1. CHEM 121Chapter 2 Winter 2015

  2. Elements and Symbols • Elements: • Chemical symbols • Ex. cobalt = nitrogen =

  3. Elements 8A 1A 2A • Ordered by atomic number • “Periodic” trends • Periodic table by Mendeleev (1871) 3A 4A 5A 6A 7A 8B 3B 4B 5B 6B 7B 1B 2B

  4. Some unusual element symbols • Au • Ag • Fe • Pb • Cu • Sn • K • Na

  5. Reading the Periodic Table Period: Group: Alkali metals: Alkaline earth metals: Halogens: Noble Gases:

  6. Metals, Nonmetals, and Metalloids • Metals: • Nonmetals: • Metalloids: • B, Si, Ge, As, Sb, Te, At

  7. Carbon Three elemental forms Interesting bonding with many elements Diamond Graphite Buckyball

  8. Element Song • Meet the elements: http://www.youtube.com/watch?v=Uy0m7jnyv6U&feature=related • All of the elements: http://www.youtube.com/watch?v=zGM-wSKFBpo&feature=related

  9. Elements of Life C N O H

  10. Other life elements Major minerals (macronutrients) Fluids: Na K Cl Proteins: Mg S Teeth & Bone: Ca P Trace elements (micronutrients) Fe Zn I F Se

  11. Molecules Molecules: Compounds: Chemical formula: How many atoms? • NaCl • H2O • CsCl2 • H2O2 • Ca(OH)2

  12. 3-minute practice How many of each type of atom is in one molecule of ammonium phosphate?

  13. Atoms and Subatomic Particles Diameter of one atom: 0.1 – 0.5 nm Charge Mass (g) Mass (amu) Location amu: atomic mass unit (1/12 C atom mass)

  14. Atomic Number and Mass Number • Atomic Number (Z) • Atoms are electrically neutral • Mass Number (A)

  15. 3-minute practice How many protons, electrons, and neutrons are in each of the following: • Z = 14 A= 29 • An atom with a nucleus with 4 protons and 5 neutrons? • A potassium atom with a mass number of 39?

  16. Isotopes Isotopes: Atomic Symbol 24 Mg 12

  17. Isotopes of Carbon 12C : 6 protons + 6 neutrons 13C : 6 protons + 7 neutrons 14C : 6 protons + 8 neutrons 98.89 % 1.11 % <0.01 % All have nearly identical chemical behavior

  18. 3-minute practice How many protons, neutrons and electrons does each of the following have? • 35Cl • 37Cl • C-14

  19. Atomic Mass weighted average of masses of all the naturally occurring isotopes of that element Example: chlorine Contribution to average Cl atom Mass (amu) x Abundance (%) = 35Cl x = 37Cl x =

  20. Relative Masses of Atoms Atoms are too small to measure actual mass Compare masses of atoms using relative mass An average Zn atom is ~ 3x more massive than an average Na atom

  21. Medical Use of Isotopes I-131

  22. Reading the Periodic Table Period: horizontal row Group: vertical column Elements in the same group have similar chemicalproperties because they have the same number of outer shell e- • Each e- in an atom “sits” at an energy level (n)

  23. Energy States • Ground state: • n = 1 • Excited states: • n = 2, 3, 4,… • Photon emitted: • Photon absorbed:

  24. Energy Sublevels • Each level consists of sublevels • # of sublevels in each level = level number • n = 1  • n = 2  • n = 3  • n = 4  Increasing energy of sublevels within an energy level:

  25. Disneyland Analogy

  26. Orbitals • Regions with the highest probability of finding an electron • Each type of orbital has a given shape: s orbital p orbitals

  27. Orbitals d orbitals Each orbital can hold _____ electrons • s orbitals: • p orbitals: • d orbitals:

  28. Orbitals f orbitals http://int.ch.liv.ac.uk/Lanthanide/Ln_Chemistry_folder/Miscellaneous%20folder/Miscellaneous.html#f_orbitals

  29. 5-minute practice • How many sublevels are in the n = 3 energy level? • What are these sublevels? How many of each type are there? • How many electrons can be held in the n = 3 energy levels?

  30. Orbital Energy Levels • Pauli Exclusion Principle: • Electrons want to sit in lowest energy level • For a given n value: Order of sublevel energy: s < p < d < f • Orbital Diagrams

  31. Electron Configurations tell us which orbitals electrons are in for a given atom Example: Hydrogen Atomic Number: (How many electrons?) Orbital Diagram: 1s Electron Configuration:

  32. Electron Configurations Example: Helium Atomic Number: (How many e-?) Orbital Diagram: Electron Configuration: Example: Lithium Atomic Number: 1s 1s 2s (How many e-?) Orbital Diagram: Electron Configuration:

  33. Electron Configurations Example: Boron Atomic Number: (How many electrons?) 2p Orbital Diagram: 1s 2s Electron Configuration:

  34. Electron Configurations Example: Oxygen Atomic Number: (How many electrons?) 2p Orbital Diagram: 1s 2s Electron Configuration: Abbreviated Configuration:

  35. Electron Configurations relate to the Periodic Table! • s block elements: end with s orbital Na: • p block elements: end with p orbitals P: • d block elements: end with d orbitals Ni: Note: 4s orbital comes before3d orbital

  36. Sublevel Order

  37. 5-minute review Write the abbreviated electron configuration for the following: • K • S • Br • Ar • Cs

  38. Periodic Trends Valence electrons: Boron (B): How many valence electrons?

  39. Periodic Trends Aluminium (Al): How many valence electrons? Chlorine (Cl): How many valence electrons?

  40. Electron Dot Symbols Lithium Valence electrons? Carbon Valence electrons? Fluorine Valence electrons?

  41. 5-minute review Draw electron dot symbols for the following: • Sulfur • Potassium • Beryllium • Silicon

  42. Elements 8A 1A 2A • Elements ordered by atomic number • “Periodic” trends • Periodic table by Mendeleev (1871) 3A 4A 5A 6A 7A 8B 3B 4B 5B 6B 7B 1B 2B

  43. Atomic Size Atomic radius:

  44. Ionization Energy Ionization:

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