1. How Does Atomic Radius Vary with in the Periodic Table

2. Important Group Names Group# - Group Name 1 – Alkali Metals
Alkaline Earth Metals
Halogens
Noble gases

3. Lets Check out the Atomic Radius of Group 1.
Li, Na, K, Rb, Cs. Atomic Radii can be found in Table S
Why is there an increase in Radius? Each Period has another layer of electrons around it.
Lets check the Atomic Radius of Group 17 F, Cl, Br, I
Compare those values with the values for group 1. Which one is larger? Does this meet your expectations?

4. There are 2 factors affecting atomic radii.
The most important is the number of electron shells. The more shells the larger the radius.
2) After accounting for number of electron shells, then the next affect is the number of protons – the more protons the smaller the atomic radius.
More protons means a stronger attraction to the nucleus causing the radius to shrink

5. C. Atomic Properties and the Periodic Table
Atomic Size
Size tends to increase down a column.
Size tends to decrease across a row.

6. How does Atomic radius vary within a group?
Increases top to bottom. Why?
Increasing number of shells of electrons.
How does atomic radius vary across periods from left to right?
Decreases left to right. Why?
Greater Nuclear Attraction due to increased number of protons

7. What is an ion? A charged particle that has gained or lost a(n) electron(s).
What would be the charge on the ion of a group 1 metal that lost an electron? How would the radius of a group 1 metal – alkali metal – change if it lost an electron?
Get much smaller Why? How many valence electrons? 1 – if it loses that what else is lost? The whole shell! Therefore the radius of a positive ion is much smaller than the radius of the atom.

8. For negative ions – gaining an – electron
For negative ions – gaining an – electron. How is the ionic radius compared to the atomic radius? Well we are trying to stuff another electron into a shell. Like charges repel so the electrons move further apart and the shell gets slightly larger.
Thus, a negative ion has a slightly larger radius than the corresponding atom’s atomic radius

9. C. Atomic Properties and the Periodic Table
Metals and Nonmetals
Metals tend to lose electrons to form positive ions.
Nonmetals tend to gain electrons to form negative ions.