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Warm Up – sit down and answer these questions right now! What is the name of the group potassium is in? Write the orbital diagram for potassium. Draw the Lewis Dot Structure for potassium. Is potassium a metal or a non-metal? List two physical properties of potassium.

Homework Study for test Rewatch videos Revise/ rewrite answers to assigned problems Use online answer keys to check your work

Review Homework Pg 6 and 7 #5, 8, 10, 11, 12 Write down questions 11 and 12 now #11: Which has a higher ionization energy: K or Ca? Explain. #12 Which has a higher ionization energy: P or S? Explain.

5 Of the elements magnesium, calcium, and barium, which forms the ion with the largest radius? The smallest? What periodic trend explains this? Barium will have the largest radius while magnesium will have the smallest. These elements are within a group. As you proceed down a group each element gains an energy level. Having additional energy levels means more core electrons and more electron shielding, making the valence electrons farther from the nucleus.

8 Explain why atomic radii decrease as you move left- to-right across a period. The number of energy levels and electron shielding remain the same but number of protons increases, increasing the effective nuclear charge. Since the valence electrons feel a greater attraction to the nucleus, the radius decreases.

10 Arrange the elements in order of increasing atomic radii and explain: Mg, N, P, Sr. N, P, Mg, Sr Nitrogen will be the smallest since it is the only atom with just two energy levels. Phosphorus and magnesium both have three energy levels, but phosphorus has more protons and a greater effective nuclear charge, so it will be smaller than magnesium. Strontium will be the largest with five energy levels.

11. Which has a higher ionization energy: K or Ca? Explain. Calcium. As you go from left to right across the periodic table the effective nuclear charge increases (because there are more protons), but the core electrons and shielding remain the same. Calcium’s valence electrons are pulled in closer to the nucleus than Potassium’s valence electrons. It requires more energy to remove an electron that is closer to the nucleus.

12. Which has a higher ionization energy: P or S? Explain. Phosphorous. Even though sulfur is a smaller atom, it is easier to remove an electron from phosphorous because the electron being removed is the P 4 electron (the first electron that is paired in the P sublevel) and removing this electron alleviates repulsion due to pairing.

Tips for a Good Answer Did you state what the trend is? (increase or decrease) Did you explain WHY? Just saying “because it increases to the left” is not enough Did you use as many vocab words as possible? (see page 4 on your packet) Take 5 minutes to look over your homework

Directions for Think-Write-Share When the music plays, walk around the room SILENTLY When the music stops, find ONE partner CLOSEST to you and greet them by name (or ask them their name) When you see the question, silently think of your answer and write it on your board Your teacher will tell you who shares first When you’re done, put your hand on your head After you’ve both shared, thank each other Repeat

Think-Write-Share How did Mendeleev arrange the periodic table? Why do we give him credit for discovering the periodic table when so many others had similar arrangements?

Think-Write-Share What is the definition for electron shielding? What is the definition for effective nuclear charge?

Think-Write-Share List vocab words needed to describe the trend of Atomic radius down a group.

Think-Write-Share Write a brief explanation for the trend of ionization energy across a period.

Think-Write-Share What are the names for the groups on the periodic table?

Think-Write-Share What is the trend for electronegativity across a period and down a column? What is the most electronegative atom on the PT?

Think-Write-Share Which are bigger within a period: cations or anions? Why?

Think-Write-Share Which is the biggest ion? Bromide or strontium Hint: start by identifying the charge each ion has

Clear Your Desk of Everything We will be going over the Ion Test and Electrons an Waves Test