PERIODIC TRENDS

CATALYST (3 MIN)

What are the following elements and what family are they in?

1. 1s22s1

2. 1s22s22p5

3. 1s22s22p63s2

4. 1s22s22p63s23p6

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

5 100

4 80

3 60

2 40

1 20

# correct out of 4

Mastery

4 100

3 75

2 50

1 25

# correct out of 3

Mastery

3 100

2 67

1 33

YOU DO: COMPLETE QUIZ 1 ALIGNMENT GUIDE (5 MIN)

# correct out of 2

Mastery

2 100

1 50

ANNOUNCEMENTSHomework: 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 Two Friday 10/12 (ODD)Monday 10/15 (EVEN)

Exam 2 Thursday 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

Trend Going from left to right this ….

Going from top to bottom this…

Atomic Number Increases Increases

Atomic Radius Decreases Increases

Ionization Energy Increases Decreases

Electronegativity Increases Decreases

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

HOMEWORK1. 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?