1. Unit 4 – Lesson 2
Periodic Table Trends

2. Periodic Trends
Specific patterns that are present in the periodic table (mostly group A elements) related to certain properties

3. 1. Atomic radius/diameter/volume (video)
Use to label chart in your notes! 1 2 3 4 5 6
n =
It is all about the SIZE of the atom NOT the mass
Atoms get larger going down a group because each period down adds one energy level (n).
Atoms get smaller going across a period because more protons pull the electrons closer to the nucleus.

4. Which is the largest atom?
F Br At
Which is the smallest atom?
K Cu Kr
Order the atoms from largest to smallest.
Br Ca Ge 3 1 2
Order the atoms from largest to smallest.
Ba C K 1 3 2

5. Noble Gases not included
2. Electronegativity (video)
Noble Gases not included
Ability to attract electrons in a chemical bond
Most electronegative  F
Least electronegative  Fr
Noble gases have very little if any electronegativity because they have full valence shells.
The more electrons an element has in its valence shell the higher the electronegativity RESULT  EN increases across periods left to right
As you move down groups, valence electrons get further away from the positive nucleus RESULT  EN decreases down a group

6. Which is atom is the most electronegative?
F Br At
Which is the least electronegative?
K Cu Kr
Order the atoms from most to least electronegative.
Ca Br Ge 3 1 2
Order the atoms from most to least electronegative.
N Bi As 1 3 2

7. 3. Ionization Energy (video)
Energy needed to pull off one electron (make an ion)
The higher the IE, the harder it is to remove an electron
Small atoms have a large IE because the electrons are very close to the positive nucleus
Atoms with a large EN have a large IE because if it is easy for the atom to grab electrons it will be very difficult to remove the electrons it has.

8. Which is atom has the highest IE?
Cl Br At
Which atom has the lowest IE?
K Cu Kr
Order the atoms from highest to lowest ionization energy.
Ca Br Ge 3 1 2
Order the atoms from highest to lowest ionization energy.
N Bi As 1 3 2

9. 4. Metallic Character
The more likely an atom is to lose an electron the stronger the metallic character
The farther the valence shell is from the nucleus the easier it is to lose an electron so metallic character increases
As electronegativity or ionization energy increases, metallic character decreases.