1. TRENDS IN THE PERIODIC
TABLE

2. Trends in the Periodic Table
 The arrangement of elements in the periodic
table into groups and periods with predictable
properties allows us to assume certain
patterns in the electron configurations.
 Other properties of elements follow predictable
patterns in the periodic table:
 Atomic Radius
 Ionization Energy
 Metallic Character
 Electronegativity

3. Atomic Radii
 Atomic radius is ½ the
distance between the
nuclei of 2 like atoms
 As you move DOWN a
group, atomic radius
INCREASES
 As you move LEFT to
RIGHT across a period
radius DECREASES

4. Atomic Radius
As you move across the period
you gain electrons but you also
gain protons. More + protons
hold their electrons tighter
As you move down the group you gain
more electrons which are in electron
orbitals further from the nucleus. The
nucleus has less pull the further out
you move.

5. Ionization Energy (IE)
 Ionization Energy is the energy required to
remove 1 electron from an atom. (Make a +
ion)
 Low IE – Easy to remove the electron
 High IE – Hard to remove the electron
 As you move DOWN a group ionization
energy DECREASES
 As you move LEFT to RIGHT across a period
ionization energy INCREASES

6. Ionization Energy
Atoms on the left of the periodic
table give up electrons easily to
achieve a more stable electron
confiTguhrea vtiaolne.nce electrons in atoms
lower in the group experience less
pull from the + protons in the
nucleus and are easier to remove.
Low IE
Lower IE
High IE
The Noble Gases have the
highest IE of all because they
are in the most stable
configuration.

7. Electronegativity
 Electronegativity is the tendency of an
atom to attract electrons in a compound.
 The higher the electronegativity, the more the atom is
able to attract electrons to itself.
 As you move DOWN a group
Electronegativity DECREASES
 As you move LEFT TO RIGHT across a
period Electronegativity INCREASES

8. Electronegativity
Electronegativity increases
across a period because the
number of charges on the
nucleus increases. That attracts
the bonding pair of electrons
more strongly.
As you go down a group,
electronegativity decreases because
the bonding pair of electrons is
increasingly distant from the attraction
of the nucleus.

9. Metallic Character
 Metallic character is the tendency of an
element to be shiny, silver, malleable, ductile
and to react to form positive ions
 As you move DOWN a group metallic
character INCREASES
 As you move LEFT TO RIGHT across a period
metallic character DECREASES

10. Metallic Character
Increasing Metallic Character

11. Overview of Trends