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Definition of periodic

Definition of periodic. Marked by repeated cycles Happening at regular intervals Example of the word periodic: Periodically Periodicals Periodic Table of Elements. Periodic Trends. Atomic Radius half of the distance between adjacent nuclei in a crystal of the element Trend

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Definition of periodic

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  1. Definition of periodic • Marked by repeated cycles • Happening at regular intervals • Example of the word periodic: • Periodically • Periodicals • Periodic Table of Elements

  2. Periodic Trends • Atomic Radius • half of the distance between adjacent nuclei in a crystal of the element • Trend • Within a period (row): DECREASES • Why? • More positive pull on electrons the same distance away Li nucleus 1s2s21 B nucleus 1s22s22p1

  3. Periodic Trends • Atomic Radius = half of the distance between adjacent nuclei in a crystal of the element • Trend • Within a group (column): INCREASES • Why? • Increasing number of energy levels Li nucleus 1s2s21 Na nucleus 1s22s22p63s1 K nucleus 1s22s22p63s23p64s1 Rb nucleus 1s22s22p63s23p64s23d104p65s1

  4. Periodic Trends • Atomic Radius • Trend • Within a period (row): • DECREASES • Within a group (column): • INCREASES

  5. Which has the largest atomic radius? • Magnesium (Mg) or Sulfur (S)? • Magnesium (Mg) or Barium (Ba)?

  6. Which element is smaller? • Nitrogen • Oxygen

  7. Which element is bigger? • Potassium • Flourine

  8. Ionic Radius = the distance from the nucleus to the outer edge of an atom with a charge • Ion = • an atom with a positive or negative charge • Valence electrons can be either gained or lost • Lose electron = lose negative charge  positive • Gain electron = gain negative charge  negative

  9. To determine the charge of ion: Charge = protons – electrons

  10. Trend • Within a period (row): • Leftside (wants to loseelectrons to get to 8): smaller positive ions • Why? When we lose electrons… • May lose of energy level • Less repulsion between electrons (electrostatic repulsion) • Right side (wants to gain electrons to get to 8): largernegative ions • Why? When we gain electrons • More repulsion between electrons (electrostatic repulsion)

  11. Ionic Radius • Trend • Within a group (column): Increase • Why? • More energy levels!

  12. Which element has the larger ionic radius? • Calcium • Oxygen

  13. Periodic Trends • Ionization Energy = • energy required to remove an electron • Think how strong does the nucleus hold it’s valence electrons? • Strong hold = High energy

  14. Octet Rule • All atoms will gain or lose electrons in order to acquire a full set of eight (two) valence electrons

  15. Ionization Energy = how strong is the nucleus’s hold on valence electrons • Within a period (row): INCREASES • Atoms get smaller as you go across—this makes it easier to hold electrons • Within a group (column): DECREASES • Atoms get bigger as you go down—this makes it harder to hold electrons Lots of energy Little energy

  16. Which element has the higher ionization energy? • Nitrogen • Oxygen

  17. Which element has the lower ionization energy? • Magnesium • Cesium

  18. Periodic Trends • Electronegativity = ability to attract electrons • Flourine (F) is the most electronegative element • Trend • Within a period (row): INCREASES • Within a group (column): DECREASES F

  19. Which element is more electronegative? • Potassium • Bromine

  20. Which element is smaller? • Sodium • Lithium

  21. Which element has the higher ionization energy? • Cesium • Oxygen

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