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Periodic Trends. 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?) - PowerPoint PPT Presentation
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Periodic Trends
Periodic TrendsOverviewFor each of the four trends (atomic radius, ionization energy, reactivity, electronegativity) You need to know:Definitions of each trendPattern 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.)
Atomic RadiusAtomic Radius: The size of the atom
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
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
Atomic RadiusAtom with smallest Atomic Radius: Helium
Atom with largest Atomic Radius: Francium
Atomic Radius PracticeWhich element has a bigger atomic radius:
Magnesium or Sulfur?
Fluorine or Iodine?
Ionization EnergyIonization Energy: The amount of energy required to lose one electron
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
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
Ionization EnergyAtom with smallest Ionization Energy: Francium
Atom with largest Ionization Energy: Helium
Ionization Energy PracticeWhich element has a bigger ionization energy:
Magnesium or Sulfur?
Fluorine or Iodine?
Periodic TrendsOverviewFor each of the four trends (atomic radius, ionization energy, reactivity, electronegativity) You need to know:Definitions of each trendPattern 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.)
ReactivityReactivity: How likely it is that the element will undergo a chemical reaction
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
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
Reactivity PracticeWhich element has more reactivity:
Sodium or Titanium?
Fluorine or Iodine?
ElectronegativityElectronegativity: The ability for an atom to gain an electron
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
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
ElectronegativityAtom with smallest Electronegativity: Francium
Atom with largest Electronegativity: Fluorine
Electronegativity PracticeWhich element has more electronegativity:
Magnesium or Sulfur?
Fluorine or Iodine?
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