Download Periodic Trends

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?)
 Compare elements using trends (of these
two elements, which has the larger… etc.)
Atomic Radius
Atomic 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 Energy
Ionization 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 Practice
Which element has
a bigger ionization
energy:
Magnesium or
Sulfur?
Fluorine or Iodine?
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.)
Reactivity
Reactivity: 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 Practice
Which element
has more
reactivity:
Sodium or
Titanium?
Fluorine or
Iodine?
Electronegativity
Electronegativity: 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
Electronegativity
Atom with
smallest
Electronegativity:
Francium
Atom with largest
Electronegativity:
Fluorine
Electronegativity Practice
Which 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