Instructions: Read the relevant text section$($s$)$; watch & take notes on the Periodic Trends video tutorial.

Then, answer these questions on the front of the sheet only prior to class.

Consider a lithium atom...

What is the electron configuration of lithium?

Using a simple "planetary" Bohr$-$model style, draw a sketch of what a lithium atom might look like.

For the sake of considering possible interparticle interactions, please draw all electrons on the

same "side" of the atom.

Is the interaction between the nucleus and each electron attractive or repulsive? Why?

Is the interaction between any two electrons attractive or repulsive? Why?

Is the strength of interaction between the nucleus and a $1s$ electron the same as the interaction

between the nucleus and a $2s$ electron? Explain.

Use the lithium atom to describe or give an example of "shielding." Refer your textbook if this term

is unfamiliar to you.

CHEM $1500-$ Periodic Trends

Assess how the strength of interaction between the nucleus and electrons affects these properties:

a$.$ When the attraction is strong, the atomic radius will be $($circle one$)$: smaller OR larger

b$.$ When the attraction is strong, the ionization energy will be $($circle one$)$: smaller OR larger

Assess how the strength of electron$-$electron repulsion affects these properties:

a$.$ When the repulsion is strong, the atomic radius will be $($circle one$)$: smaller OR larger

b$.$ When the repulsion is strong, the ionization energy will be $($circle one$)$: smaller OR larger

Answer these questions about the general periodic trends in atomic radius:

a$.$ As you go left to right across a row of the periodic table, the radius: increases OR decreases

i$.$ The most important concept for explaining this is: nuclear charge OR shielding

b$.$ As you go down a group of the periodic table, the radius: increases $OR$ decreases

i$.$ The most important concept for explaining this is: nuclear charge $OR$ shielding

Which element in each pair is larger? Why?

a$.Na$ or $K$

b$.N$ or $O$

c$.F$ or $S$

Which element in each pair has a larger ionization energy? Why?

a$.Cl$ or $Ar$

b$.K$ or $Rb$

The ionization energy of oxygen is slightly less than the IE of nitrogen. Why? Use orbital notation

if it helps!