Do Now Work silently. Raise hand to ask Ms. Hughes anything. 1.Which family is least reactive? 2.Which family is most metallic? 3.Where are the nonmetals on the periodic table?

Announcements Unit 4 test tomorrow If you have not taken 3 chemistry tests yet this semester, see me after to arrange a make up Retake GLEs for GRADE BOOST

Mystery Element Definitely NOT a Metalloid 3rd Most Common Element in Earth’s Crust Light weight / Good Conductor Because it is a good conductor, it makes a great beverage can…but its resistance to corrosion means lots of space in land fills

Valence Electrons Don’t forget! Valence electrons are the electrons in the outermost energy level.

Example Electron configuration for silicon (Si): What is the highest energy level? So how many valence electrons? 1s 2 2s 2 2p 6 3s 2 3p = 4!

Valence Electrons

Family/GroupNumber of Valence Electrons Alkali Metals Alkaline Earth Metals Boron’s Group Carbon’s Group Nitrogen’s Group Oxygen’s Group Halogens Noble Gases

What is Atomic Size? Atomic size is… –How big an atom is –Also known as atomic radius

Graphing Atomic Size (Radii) Draw 2 line graphs –X-axis: Element –Y-axis: Atomic Radius (picometers)

Elements and their Atomic Radii (1) ElementAtomic Radius Hydrogen37 Lithium152 Sodium186 Potassium227 Rubidium248 Cesium265 1 picometer = 1 x m

Elements and their Atomic Radii (2) ElementAtomic Radius Lithium152 Beryllium112 Boron85 Carbon77 Nitrogen75 Oxygen73 Fluorine72 Neon71 1 picometer = 1 x m

Atomic Size – Graph 1 HLi NaKRbCs

Atomic Size – Graph 2 Li BeB CN O F Ne

What trend(s) do you notice?

Atomic size DECREASES as you go across the Periodic Table Atomic size INCREAESES as you go down thePeriodic Table

Atomic Size Key Point #1: Atomic size increases as you go down the periodic table and to the left

Practice Problems Rank the following elements in order of increasing atomic size based on location on the periodic table (smallest to biggest) Fr, Sc, P, Pd F, As, Tl, S P, Pd, Sc, Fr Fluorine, Sulfur, Arsenic, Thallium

Practice Time! 1.T or F? Atomic size decreases as you move right across the periodic table. 2.T or F? As you move down the Periodic Table, atoms get smaller. 3.Rank the following sets of elements in order of increasing atomic size (small  big). Set A: Bh, Mn, Re, TcSet B: Sb, I, Ag, Ru Set C: Y, Ti, Sg, Ta 4.Rank the following sets of elements in order of decreasing atomic size (big  small). Set A: Cl, At, I, F, BrSet B: Te, Xe, Sn, In Set C: Rb, K, Sr, Ca

How metallic? How metallic an element is changes periodically too!! Hard, shiny, solid, conducts electricity, malleable, ductile Same pattern as atomic radii Elements become more metallic as you move left and down on the periodic table

What is electronegativity? Electronegativity is… –The ability of an atom to attract electrons –How much an atom wants electrons –How easily an atom accepts electrons

Graphing Electronegativity Draw 2 line graphs –X-axis: Element –Y-axis: Electronegativity (Paulings)

Elements and their Electronegativity (1) ElementElectronegativity Hydrogen2.20 Lithium0.98 Sodium0.93 Potassium0.82 Rubidium0.82 Cesium0.79 Francium0.70

Elements and their Electronegativity (2) ElementElectronegativity Lithium0.98 Beryllium1.57 Boron2.04 Carbon2.55 Nitrogen3.04 Oxygen3.44 Fluorine3.98

Electronegativity Graph 1

Electronegativity Graph 2

What trend(s) do you notice?

Electronegativity Trends

Electronegativity Key Point #2: Electronegativity increases as you go up the periodic table and to the right across the periodic table.

Practice Problems Rank the following elements in order of increasing electronegativity based on location on the periodic table (smallest to biggest) Mg, Sr, Be, Ra Cl, Si, Al, S, P Radon, Strontium, Magnesium, Beryllium Aluminum, Silicon, Phosphorus, Sulfur, Chlorine

Practice Time! 1.T or F? Electronegativity decreases as you move left across the periodic table. 2.T or F? As you move down the Periodic Table, atoms get more electronegative. 3.Rank the following sets of elements in order of increasing electronegativity (small  big). Set A: Bh, Mn, Re, TcSet B: Sb, I, Ag, Ru Set C: Y, Ti, Sg, Ta 4.Rank the following sets of elements in order of decreasing electronegativity (big  small). Set A: Cl, At, I, F, BrSet B: Te, Xe, Sn, In Set C: Rb, K, Sr, Ca

How does atomic size related to electronegativity? Key Point #3: Atomic size is indirectly related to electronegativity. ELECTRONEGATIVITY ATOMIC SIZE As electronegativity increases, atomic size decreases!

Why is this relationship true? Atoms with HIGH ELECTRONEGATIVITIES hold their electrons very close! Sooooo, the atomic size decreases High or low electronegativity? Large or small atomic size?

Ionization Energy The energy required to remove 1 electron from an atom

What do you think is the relationship between ionization energy and electronegativity?

The more an atom wants an electron (electronegativity) the more energy it will take to remove that electron (ionization energy) So same pattern!!!

Ionization energy Key Point #3: Ionization energy increases as you go up the periodic table and to the right across the periodic table.

Electron Affinity Very similar to other 2 How much an atom likes electrons Key Point #4: electron affinity increases as you go up the periodic table and to the right across the periodic table.

Done early? Start review sheet!!!

Exit Slip 1.What are the 3 atomic trends we studied? 2.How does each increase across the periodic table HW: –Unit 4 review sheet Top Ten: how’d we do?