Q of the Day 1. The octet rule explains that Sulfur wants ___ valence electrons so it will gain ___ and form a ____ ion. Day

Periodic Trends Ionization energy – energy needed to remove one electron from an atom Li → Li + + e - ionization energy = 8.64e-19 J/atom … indication of how strongly an atom holds onto its outermost elecs.

Periodic Trends The graph on page 178 shows how ionization energies vary with atomic # First ionization energy (kJ/mol) Atomic number

Periodic Trends First ionization energy (kJ/mol) Atomic number What element does the point at (5, 800) represent?

Periodic Trends With respect to the periodic table ionization energies show 2 important trends… 1. Decrease as you move down a group 2. Increase as you move left to right across a period

Periodic Trends How does the ionization energy trend compare to the atomic radius trend? Does this make sense?

Periodic Trends O Be Cl What’s bigger:↑er I. E.: O or C Be or Ca Na or Be Cl of Al Ca or B +3

Read Section 6.3 and complete #s on page 182

Day Why are H and He both in period 1? 1.Which of the following are larger? Ne OR Br -1  Give all 3 reasons why (BE SPECIFIC!). 2. Why are Ar and Kr both in group 18??

Day Get out your lab, which unknowns turned pink with the addition of solution C (when you are done you should have 3)?

Day Hints for your lab data: - every solution should form one precipitate (either with A or B) - 3 of your solutions should turn pink with the addition of C - 6 of your precipitates should dissolve with the addition of D

Day Get out your lab, postlab, and review!!! 2. The test will be Friday Postlabs (both parts) are due Wednesday The review should be finished by Thursday 3-19.

Day What are 3 things that ALL noble gases have in common?

Periodic Trends Successive Ionization energies (removing more than one electron from an atom): - The 2 nd > 1 st, the 3 rd > 2 nd, the 4 th > the 3 rd - but if you look think about I. E. s there is usually a large jump. Where?

As of today, you should already have the following: Families colored in (page 168) Valence electrons marked +1, +2, -1,-2, and -3 ions marked Reactivity trend (front / back) Atomic size (front / back) Electronegativity (front / back)

Added today: Ionization energy (front / back) Day Ionization energies are higher for smaller atoms!

Day Get out your lab, postlab, and review!!! 2. The test will be Friday 3-20 and you will hand in your colored periodic table. 3. Postlabs (both parts) are due tomorrow. 4. The review should be finished by Thursday 3-19.

YOU WILL HAVE EXACTLY 3 MINUTES FROM THE TIME THE BELL RINGS TO FINISH AND THEN HAND IN YOUR ATB.

Day Why are the alkali metals and the halogens so reactive? 1.Which of the following are larger? Na OR Be +2  Give at least 2 specific reasons why. 2. Why are Mg and Sr both in group 2?

3. Why are the alkali metals and the halogens so reactive? 1.Which of the following are larger? Al +3 OR Rb  Give at least 2 specific reasons why. 2. Why are Mg and S both in period 3? Day

3. Why are the alkali metals and the halogens so reactive? 1.Which of the following are larger? Cl - OR Ne  Give at least 2 specific reasons why. 2. Why are Br and I both in group 17? Day

3. Why are the alkali metals and the halogens so reactive? 1.Which of the following are larger? Ar OR Se -2  Give at least 2 specific reasons why. 2. Why are Na and S both in period 3? Day

1. Get out your lab, postlab, and NOTES!!! 2. The test will be Friday 3-20 and you will hand in your colored periodic table. 3. Postlabs (both parts) are due NOW. 4. The review should be finished by Thursday 3-19.

Bigger down a group and smaller across a period How does atomic radius change? Why? As you move down a group, there are additional energy levels As you move across a period there are additional protons pulling the electron in tighter

Negative ions get bigger Positive ions get smaller How does ion size change? Why? Negative ions gain electrons Positive ions lose electrons

Opposite of size (atomic radius) How does ionization energy change? Why? Electrons are closer to the nucleus and held tighter in smaller atoms

Away from the middle How does reactivity change? Why? Atoms on the outside of the p.t. are closer to achieving the octet rule and so more reactive

Increases up and to the right (Fr to F) Elements on the right side of the periodic table want electrons to satisfy the octet rule How does electronegativity change? Why?

YOU WILL HAVE EXACTLY 3 MINUTES FROM THE TIME THE BELL RINGS TO FINISH AND THEN HAND IN YOUR ATB.

Day Why are H and He both in period 1? 1.Which of the following are larger? Ne OR Br -1  Give 2 reasons why (BE SPECIFIC!). 2. Why are Ar and Kr both in group 18??

Day Why are H and K both in group 1? 1.Which of the following are larger? F -1 OR He  Give 2 reasons why (BE SPECIFIC!). 2. Why are Cs and Ba both in period 6??

Day Why are Be and N both in period 2? 1.Which of the following are larger? Sr +2 OR Cs  Give 2 reasons why (BE SPECIFIC!). 2. Why are Br and I both in group 17??

Day Why are Al and Cl both in period 3? 1.Which of the following are larger? B +3 OR Mg  Give 2 reasons why (BE SPECIFIC!). 2. Why are Kr and Ne both in group 18??

Day Get out your REVIEW!!! 2. The test will be Friday 3-20 and you will hand in your colored periodic table. 3. Postlabs (both parts) are late. 4. The review should be finished by NOW.

The test will be FRIDAY 3-20!!! BRING your COLORED PERIODIC TABLE and your REVIEW!!!