PERIODIC TRENDS

CATALYST (3 MIN) What are the following elements and what family are they in? 1.1s 2 2s 1 2.1s 2 2s 2 2p 5 3.1s 2 2s 2 2p 6 3s 2 4.1s 2 2s 2 2p 6 3s 2 3p 6

YOU DO: COMPLETE QUIZ 2 ALIGNMENT GUIDE (5 MIN) Step 1: Mark the incorrect answers on your answer sheet. Step 2: Fill in the number correct on your alignment guide in the “Score” column. Step 3: Calculate the percent correct for each set of questions. Write this in the “Mastery” column. Step 4: Answer the Questions below the table.

# correct out of 5 Mastery # correct out of 4 Mastery # correct out of 3 Mastery YOU DO: COMPLETE QUIZ 1 ALIGNMENT GUIDE (5 MIN) # correct out of 2 Mastery

ANNOUNCEMENTS Homework: Quiz two study guide, due day of quiz Office hours Wednesday and Friday Test corrections any time during office hours Unit 2 exam and quiz schedule: Quiz TwoFriday 10/12 (ODD) Monday 10/15 (EVEN) Exam 2Thursday 10/18 (ODD) Friday 10/19 (EVEN)

OBJECTIVE  SWBAT determine the periodic trends per group and period of main elements  SWBAT relate the reactivity of elements to their electron structure

IONIZATION ENERGY Ionization energy is the energy needed to steal an electron away from an atom. When an electron is removed the atom becomes a positive ion. LOW Ionization energy = VERY Reactive!!

TRENDS IN IONIZATION ENERGY Ionization energy increases from left to right across a period. # of protons increases, positive nucleus pulls the electrons closer, harder to pull one electron off. Ionization energy decreases down a group electrons are farther from the nucleus, easier to pull one electron off

IONIZATION ENERGY TRENDS

EXAMPLE: IONIZATION ENERGY QUESTION Which element has the lowest ionization energy? Lithium Sodium Cesium Rubidium

GUIDED EXAMPLE: IONIZATION ENERGY EXAMPLE 1 Which element has the lowest ionization energy? Gallium Germanium Arsenic Bromine EXAMPLE 2 Which element has the highest ionization energy? Magnesium Barium Radon Strontium

#6.3 Aim: What trends do we see on the Periodic Table? Agenda QOD (10) Activity : graphing atomic radii (15) Share : trends (5) Lesson: periodic trends(15) HW #3

ELECTRONEGATIVITY Electronegativity is the interest of atoms in attracting or keeping electrons. An atom that is electronegative is an electron thief.

PERIODIC TRENDS IN ELECTRONEGATIVITY Electronegativity increases from left to right across a period. # of protons increases, nucleus pulls the electrons closer, easier to attract an electron Electronegativity decreases down a group. electrons are farther from the nucleus, harder to attract an electron

ELECTRONEGATIVITY

EXAMPLE: ELECTRONEGATIVITY QUESTION Which element has the highest electronegativity? Silicon Aluminum Sulfur Phosphorous

GUIDED EXAMPLE: ELECTRONEGATIVITY EXAMPLE 1 Which element has the lowest electronegativity? Gallium Germanium Arsenic Bromine EXAMPLE 2 Which element has the highest electronegativity? Magnesium Barium Radon Strontium

ATOMIC RADIUS Atomic radius is how wide an atom is The radius of an atom is directly related to its size. Bigger radius=Bigger atom

Atomic radii  Radius  = a measure of the size of an atom

EXAMPLE: ATOMIC RADIUS QUESTION Which element has the largest atomic radius? Boron Gallium Titanium Indium METHOD 1)Question Asking? Atomic Radius 2)Horizontal or VerticalTrend? Vertical 3)“Biggest” or “Smallest”? Biggest 4)Direction of Arrow? Small to Big 5)Answer  ?

GUIDED EXAMPLES: ATOMIC RADIUS EXAMPLE 1 Which element has the smallest atomic radius? Krypton (Kr) Germanium (Ge) Calcium (Ca) Arsenic (As) EXAMPLE 2 Which element has the largest atomic radius? Silicon (Si) Lead (Pb) Carbon (C) Germanium (Ge)

PERIODIC TRENDS SUMMARY TABLE TrendGoing from left to right this …. Going from top to bottom this… Atomic NumberIncreases Atomic RadiusDecreasesIncreases Ionization EnergyIncreasesDecreases ElectronegativityIncreasesDecreases

WE DO: PERIODIC TRENDS TABLE (15 MIN) Write the definitions for each trend Use the chart to write the # value for each trend on the table When finished, look at the numbers and write whether the trend is increasing or decreasing

THEY DO: PERIODIC TRENDS WAR GAME (20 MIN) Pick a partner and grab a bag of cards Place a card down, the one with the greater value for the trend wins both cards Repeat until one player has all the cards If you put down the same card, play ‘war’

YOU DO: BOOK PRACTICE PROBLEMS (20 MIN) Complete the following book problems to turn in at the end of class: p.182 #18, 22, 24, 25 p. 186 #38, 41, 45, 48

HOMEWORK 1.Which has the largest atomic radius: nitrogen (N), antimony (Sb), or arsenic (As)? The smallest? 2.For each of the following properties, indicate whether fluorine or bromine has a larger value. Electronegativity Atomic radius Ionization energy Atomic number 3.Which element in each pair has the larger ionization energy? Li, N Kr, Ne Cs, Li

CLOSING 1.How does the organization of elements on the periodic trend reflect the electron structure of each element? 2.How does the electron structure of an element determine physical and chemical properties of that element?