1. Periodic Trends

2. Periodic Trends Overview For each of the four trends (atomic radius, ionization energy, reactivity, electronegativity) You need to know:  Definitions of each trend  Pattern of the trend (where on the periodic table is this trend the highest? The lowest?)  Compare elements using trends (of these two elements, which has the larger… etc.)

3. Atomic Radius Atomic Radius: The size of the atom

4. Atomic Radius  As we move across (left to right) the periodic table, atomic radius decreases  Atom starts out the same size but increase the number of protons and electrons  With more protons and electrons they attract and pull together more, making the atom smaller

5. Atomic Radius  As we move down the periodic table, atomic radius increases  Each time we move down a row the atom grows one energy level

6. Atomic Radius Atom with smallest Atomic Radius: Helium Atom with largest Atomic Radius: Francium

7. Atomic Radius Practice Which element has a bigger atomic radius: Magnesium or Sulfur? Fluorine or Iodine?

8. Ionization Energy Ionization Energy: The amount of energy required to lose one electron

9. Ionization Energy  As we move across (left to right) the periodic table, ionization energy increases  As you move across the periodic table the number of valence electrons increases  As the number of valence electrons gets closer to 8, the harder it is to remove an electron

10. Ionization Energy  As we move down the periodic table, ionization energy decreases  Each time we move down a row the atom gets bigger, creating more space between the protons and electrons  With more space between the protons and electrons it is easier to remove an electron

11. Ionization Energy Atom with smallest Ionization Energy: Francium Atom with largest Ionization Energy: Helium

12. Ionization Energy Practice Which element has a bigger ionization energy: Magnesium or Sulfur? Fluorine or Iodine?

13. Periodic Trends Overview For each of the four trends (atomic radius, ionization energy, reactivity, electronegativity) You need to know:  Definitions of each trend  Pattern of the trend (where on the periodic table is this trend the highest? The lowest?)  Compare elements using trends (of these two elements, which has the larger… etc.)

14. Reactivity Reactivity: How likely it is that the element will undergo a chemical reaction

15. Reactivity  As we move across (left to right) the periodic table, reactivity decreases, then increases  As you move across the periodic table the number of valence electrons increases, making it less reactive, then more reactive  The last column is not reactive at all

16. Reactivity  As we move down the periodic table, reactivity generally increases  Each time we move down a row the atom gets bigger, creating more space between the protons and electrons  With more space between the protons and electrons it is easier to gain or lose electrons, undergoing reactions

17. Reactivity Practice Which element has more reactivity: Sodium or Titanium? Fluorine or Iodine?

18. Electronegativity Electronegativity: The ability for an atom to gain an electron

19. Electronegativity  As we move across (left to right) the periodic table, electronegativity increases  As you move across the periodic table the number of valence electrons increases  As the number of valence electrons gets closer to 8, the easier it is to gain an electron

20. Electronegativity  As we move down the periodic table, electronegativity decreases  Each time we move down a row the atom gets bigger, creating more space between the protons and electrons  With more space between the protons and electrons it harder for an electron to become attracted to the protons

21. Electronegativity Atom with smallest Electronegativity: Francium Atom with largest Electronegativity: Fluorine

22. Electronegativity Practice Which element has more electronegativity: Magnesium or Sulfur? Fluorine or Iodine?

23. Notice… Ionization Energy and Electronegativity have the same trends… Atoms that need more energy to remove an electron are also more likely to gain an electron Big Ionization Energy = Big Electronegativity