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 Radius

Atom with smallest Atomic Radius: Helium

Atom with largest Atomic Radius: Francium

Atomic Radius Practice

Which 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 Energy

Atom 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