1. Periodic Trends

2. Atomic Radius
The distance from the nucleus out to the _______________(outermost energy level occupied by electrons)
Measured in
angstroms ( )

3. How Radius Is measured The point at which the valence shell “ends” is
difficult to measure.
Instead, the distance
between the _________ of 2
bonded atoms is divided
by 2, as nuclei are more
easily detected

4. Atomic Properties affecting radius
Energy Levels:
The more energy levels required to hold an atom’s electrons, the larger the radius will be.
As each energy level gets further and further from the nucleus.

5. Atomic Properties affecting radius
Electron Shielding: Core electrons block (shield) the positive charge of the nucleus that the outer (valence) electrons feel.

6. Atomic Properties affecting radius
Electron Shielding:
The more _____________present, the more shielding of the nuclear charge.
The more the positive charge is shielded, the __________ the radius will be as the attraction force between the electrons and protons will be less.

7. Atomic Properties affecting radius
Nuclear Charge
The overall positive charge emitted
from the nucleus due to the number
of _____________ present.
The more protons in the nucleus, the greater the charge.
The greater the nuclear charge,
the greater the attractive force
between the nucleus and the
orbiting electrons, the smaller the ____________.

8. Nuclear Charge vs. electron shielding
Nuclear charge & electron shielding work against each other, often canceling each other out.
This results in an “__________
___________________”, or the
charge valence electrons
actually feel after the
affects of shielding by core
electrons.
What is the effective charge felt
by sodium’s 1 valence electron?

9. Effective Nuclear Charge

10. Periodic Trend for radius
_____________ down a group, ____________ across a period.
Why?!

11. Explaining Radius trends
Down a ___________ Reason:

12. Explaining Radius trends
Across a ____________ Reason:

13. Affects of Atomic Radius
Atomic Radius is the determining factor behind the characteristics of _________________ and _____________
______________.
In other words, you can explain why an atom has a certain electronegativity or ionization energy by referencing its radius.

14. Electronegativity
The ability of an atom to attract another atom’s ___________________ towards itself.

15. Electronegativity
Remember that, when atoms bond, they attempt to _________ or _________________ valence electrons.
Electronegativity is a measure of how well an
atom can steal away
another atom’s valence
electrons.

16. Electronegativity
______________ is the determining factor for electronegativity.
The closer an atom can
get it’s nucleus (positive
attractive force) to the
valence electron it is
trying to steal, the more
it can attract it.

17. Electronegativity
When we say the radius is the determining factor for electronegativity, we are also saying that the balance between the nuclear charge, electron shielding, and the number of energy levels determines electronegativity
Because they determine radius!

18. Trends for Electronegativity
Radius and Electronegativity are __________________ related (as one increases, the other decreases)

19. Ionization energy
The energy required to _____________ a valence electron from an atom (how hard it is to remove).

20. Ionization energy
_______________ is the determining factor for ionization energy.
The closer an atom’s nucleus
(positive attractive force) is to
it’s own valence electrons
the more it can attract them
and the harder they will be
to remove.

21. Ionization energy
Again, when we say the radius is the determining factor for ionization energy, we are also saying that the balance between the nuclear charge, electron shielding, and the number of energy levels determines ionization energy.
Because they determine radius!

22. Trends for ionization energy
Radius and Ionization Energy are ________________ related (as one increases, the other decreases)

23. Ionization Energy and Electronegativity
Both ionization energy and electronegativity describe how an atom handles ___________________________
Whether it is good at taking electrons or good at giving them
Therefore, it should be no surprise that we use this information to determine how they _______________ and what ___________ of bonds these atoms make!
Bonds