Bellwork Analyze the Bohr model on the piece of butcher paper on your desk. 2.5 min: Write down everything you know about the element in your own section. Valence electrons, reactivity, group, period etc. 3.5 min: Talk with your group and come to a consensus on the information you want to include in the center square 4.Present center information to the class - Pick a spokesperson for this!

Bellwork: Honors With your group, take 5 minutes to finalize plans for you video 2.You will only have 10 minutes to film and get it right! Don’t forget to include everything on the note taker (valence e- and elements for groups 1, 2, 7, 8) and one thing you researched! 3.Designate 1 person in your group to get a lap top and sign it out 4.BE CAREFUL WITH LAP TOPS WHEN FILMING!

Butcher Paper Activity 1.Analyze the Bohr model on the piece of butcher paper on your desk. 2.5 min: Write down everything you know about the element in your own section. Valence electrons, reactivity, group, period etc. 3.5 min: Talk with your group and come to a consensus on the information you want to include in the center square 4.Present center information to the class - Pick a spokesperson for this!

Objective You will be able to analyze a Bohr model of a specific element and determine all properties of that element that we have discussed (valence electrons, reactivity, group, periodic table trend)

Periodic Table Trends 1.Atomic radius 2.Ionization energy 3.Electronegativity

- As you go up in period #, you add an energy shell of electrons or another orbital - As you go up in group #, you add an electron to the outer electron shell (excluding the transition metals) Number on top of each group = valence electrons (ignore the 1 for groups 13-18)

On Your Butcher Paper Write down how many energy shells (orbitals) the element has - Keep in mind, these are shells that CONTAIN electrons

Real model of the atom

1. Atomic Radius Atomic radius The distance from the nucleus to the outmost electrons depending on pull from protons Thought question: But the electrons can be anywhere as we just discussed in the last slide… so how can we predict where the outermost electrons are?

Atomic Radius Example 1 – Right  Left: Compare Potassium (K) and Krypton (Kr) Which do you think has a bigger atomic radius - Period (outermost shell) - Valence electrons - # of Protons Talk with your neighbor

Atomic Radius

Potassium Krypton Which has a larger atomic radius?

Atomic Radius Answer: Shells: They are in the same Period so they both have the same number of shells (orbitals) Valence e-: Kr has more valence shell electrons but they are in the same orbital as K Protons: Kr has more protons in the center than K Protons pull on electrons so the electrons in Kr are being pulled inward more Result: Kr is smaller than K

Atomic Radius Conclusion Ex. 1 – Right  Left Atomic radius increases as you go right  left Because the fewer protons there are, the smaller the pull on electrons allowing radius to be larger Mark on your table at the bottom

Atomic Radius Example 2: Top  Bottom Compare Lithium (Li) and Cesium (Cs) Which has a bigger atomic radius and why? Talk with a neighbor

Atomic Radius

Cesium Which has a larger atomic radius?

Atomic Radius Answer: Shells: Li has fewer electron shells than Cs Valence e-: Li and Cs have the same number of valence electrons Protons: Cs has more protons so more pull but it they cannot reach the outer shells as well Result: Li is smaller than Cs

Atomic Radius Conclusion: Atomic radius increases as you go DOWN the periodic table Because added energy shells (orbitals) increases the distance of electrons from the nucleus Mark on your table to the left

Practice with a neighbor 1.Which element has a larger atomic radius, Strontium (Sr) or Silver (Ag)? WHY? 1.Which element has a SMALLER atomic radius, Magnesium (Mg) or Rubidium (Rb)? WHY? Strontium – less protons, less pull on e- more making atom bigger Magnesium – fewer shells, e- closer to nucleus

On Your Butcher Paper Is the atomic radius of your element big or small? Choose an element to compare it to (using left/right or up/down trends) Explain to your group.

Bellwork Get out homework packet on trends, I will be stamping EACH section (3 stamps total) 2.What group on the periodic table is Francium (Fr) in? 3.How many valence electrons does Francium (Fr) have? 4.How many energy shells does Francium (Fr) have? **Pass back homework packets

Element of the Day – Hydrogen

2. Ionization Energy Ionization Energy: The amount of energy required to remove one electron from the outermost shell of an element Question: What do you think is most important to consider when determining ionization energy of an element?

2. Ionization Energy Example 1: Left  Right Which element has a higher ionization energy, Lithium or Fluorine? Why? - Think about valence electrons Talk with your neighbor

Ionization Energy

Which has a higher ionization energy?

Ionization Energy Answer: Valence electrons: Fluorine almost has a full outer shell of electrons and does not want to give them up. Lithium has only one and will willingly give it up to Fluorine Result: Fluorine has a higher ionization than Lithium

Ionization Energy Conclusion: Ionization energy increases as you go left  right - Because it gets harder to pull electrons away from elements with almost full outer shells Mark on your table on the top

Ionization Energy Example 2: Bottom  Top Which has a higher ionization energy, Iodine (I) or Fluorine (F)? Why? - Think about atomic radius Talk with a neighbor

Ionization Energy

Answer: Valence electrons: same in both Atomic radius: iodine has a larger atomic radius than fluorine so electrons are farther away from the nucleus and thus have a weaker pull on them from the nucleus Result: Fluorine has a higher ionization energy

Ionization Energy Conclusion: Ionization energy increases as you go from bottom to top - Because it gets harder to pull away an electron as they get closer to the nucleus due to the pull of protons Mark on your table on the right

Practice with a neighbor 1.Which element has a higher ionization energy, Carbon (C) or Neon (Ne)? WHY? 1.Which element has a SMALLER ionization energy, Cesium (Cs) or Sodium (Na)? WHY? Neon – full outer shell of e-, harder to remove e- Cesium – more e- shells, outer electrons easier to remove

On Your Butcher Paper Pick an element on the periodic table in the same period OR group as your element Is the ionization of your element HIGH or LOW compared to the one you chose? Explain to your group

3. Electronegativity Electronegativity The amount of attraction the element has for electrons (how much it hogs e-) Also called ELECTRON AFFINITY – how badly an element wants electrons to eventually become stable Thought Question What do you think determines an elements “desire” for electrons?

3. Electronegativity Example 1: Left  Right Which is more electronegative, sodium (Na) or chlorine (Cl) and why? - Think about valence electrons Talk with your neighbor

Electronegativity

SodiumChlorine

Electronegativity Answer: Valence electrons: Chlorine has more valence shell electrons (7 e-) than sodium (1 e-) and therefore wants more electrons to fill its shell and become stable Conclusion: Electronegativity increases as you go from left  right - Because elements have more electrons in their valence shell and WANT more to become stable (full outer shell) Mark on your table on the top

Electronegativity Example 2: Bottom  Top Is Selenium (Se) more or less electronegative than Oxygen (O)? Why? - Think about atom radius and number of valence shells Talk with a neighbor

Electronegativity

Selenium

Electronegativity Answer: Valence electrons: all have 1 valence electrons Atomic radius: Barium has more electron shells and therefore electrons are farther away from the nucleus and not held as tightly. Beryllium has fewer electron shells and therefore holds electrons more tightly so it WANTS them more. Conclusion: Electronegativity increases as you go from bottom  top - Because elements have a smaller radius at the top and hold onto electrons more tightly (want them more) Mark on your table on the right

Practice with a neighbor 1.Which element has a higher electronegativity (electron affinity), Argon (Ar) or Magnesium (Mg)? WHY? 2.Which element has a LOWER electronegativity, Xenon (Xe) or Neon (Ne)? Argon – full outer shell of e-, does not want to give up Xenon – more electron shell, outer e- not held as tightly (doesn’t want them as much)

On Your Butcher Paper Choose an element on the periodic table in the same period OR group as your element. Is the electronegativity of your element HIGHER or LOWER compared to that element? Explain to your neighbors.

Topics to be covered on quiz Wed. 1.Average atomic mass (honors only) 2.History of periodic table – from notes Who came up with the table we use today and how did he construct it? 3.Periodic table groups – from note-taker Given a Bohr model, tell me what group, reactivity, # of valence e- 4.Periodic table trends – from notes and HW Given two elements, which is more electronegative? Why? Given two elements, which has a larger atomic radius? Why? Given two elements, which has a higher ionization energy? Why?

Which element has a SMALLER atomic radius? WHY? Br K

Which element has a LARGER atomic radius? WHY? SPo

Which element is more electronegative? WHY? C F

Which element has a LOWER electronegativity? WHY? XeHe

Which element is has a HIGHER ionization energy? WHY? PMg

Which element has a LOWER ionization energy? WHY? Cs K

Exit Slip What are two things you need to look at when determining atomic radius? 2.What are two things you need to look at when determining ionization energy? 3.What are two things you need to look at when determining electronegativity? Homework – COMPLETE trends packet due Wednesday Quiz Wednesday # of protons, # of energy shells # of valence electrons, atomic radius (pull of protons) # of valence electrons, atomic radius (pull of protons)

Steps to Solving Trend Problems Atomic Radius – size of atom 1.Find the elements on the periodic table 2.If Left – Right  look at # of protons a.More protons = more pull = smaller radius b.Less protons = less pull = larger radius 3.If Up – Down  look at # of shells a.More shells = larger radius b.Less shells = smaller radius

Steps to Solving Trend Problems Ionization Energy – energy needed to remove e- 1.Find the elements on the periodic table 2.If Left – Right  look at # of valence electrons a.More valence electrons = harder to pull away = higher ionization energy b.Less valence electrons = easier to pull away = lower ionization energy 3.If Up – Down  look at # of shells a.More shells = lower ionization energy because electrons farther from nucleus (easier to remove) b.Less shells = higher ionization energy because electrons closer to nucleus (harder to remove)

Steps to Solving Trend Problems Electronegativity – desire for or attraction to electrons 1.Find the elements on the periodic table 2.If Left – Right  look at # of valence electrons a.More valence electrons = more attracted to electrons = higher electronegativity b.Less valence electrons = less attracted to electrons = lower electronegativity 3.If Up – Down  look at # of shells a.More shells = lower electronegativity because electrons farther from nucleus (not as attracted) b.Less shells = higher electronegativity because electrons closer to nucleus (more attracted)