Periodic Trends Notes:
The periodic table is organized by increasing _______________________ and similar
______________________________________.
Similarities in properties and reactivity that exist are directly related to the similar
valence electron configuration of the elements in the same ______________.

_______________ electrons are those found in the highest energy level in an
atom’s structure.

Elements that fall in the same group have the same
_______________________________________________________________
and thus _______________________________________________________.
Periodic Trends: overall change in physical property through row or group on the periodic
table. These are general trends (there are exceptions).

Period Trends: Examine in how a property changes as we move from ____________
to __________ across the periodic table.

Group Trends: Examine in how a property changes as we move from ____________
to __________ in a column the periodic table.
Trend #1: Atomic Radius
The outer edge of the electron cloud does not have a clearly defined edge. It is the region
where there is a 90% probability of finding the electrons.
Atomic radius__________________________________________________________
____________________________________________________________________.
Draw:
Group Trend:
As you go from top to bottom down a group; the atomic radius ________________.
2 reasons:
1)
2)
Row Trend:
As you go from left to right across a period; the atomic radius _______________.
Reason:
Trend #2: Ionic Radius
There are separate trends for cations and anions because:
Cations (positive ions) generally are smaller than their respective atoms because a
___________________________________ occurs.
Example:
Anions (negative ions) generally are larger than their respective atoms because a
___________________________________ occurs.
Example:
Trend #3 – Ionization Energy (IE)
Ionization energy is ___________________________________________________
____________________________________________________________________.
Equation:
This is an ______________________ reaction (heat is absorbed), so all ionization
energies will be positive values.
↓ Group Trend:
As you go from top to bottom down a group; the IE ________________________.
Reason:
↑Row Trend:
As you go from left to right across a period; the IE __________________.
Reason:
Trend #4 – Electronegativity (en) and Electron Affinity
Electronegativity is ____________________________________________________.

Electronegativity values are relative values (no units) that range from 0.0 to 4.0.
↓Group Trend:
As you go from top to bottom down a group; the en ________________________.
Reason:
↑Row Trend:
As you go from left to right across a period; the en ________________________.
Reason: