Drill Determine the group and period of the following: Determine the group and period of the...

DrillDrill

Determine the group and period of the Determine the group and period of the following:following:

a.a. Mg Mg

b.b. Ar Ar

c.c. N N

ObjectiveObjective

SWBAT: SWBAT: ExploreExplore the arrangement of the periodic table in the arrangement of the periodic table in

order to identify its trends. order to identify its trends.

SAT/HSA EnrichmentSAT/HSA Enrichment

Male fiddler crabs attract females by quickly waving their large front claw. If a claw is lost in a fight or accident, they quickly grow a hollow claw of equal length. Because the new claw is lighter, they can wave it faster.

The new claw probably helps the male fiddler crab to

a. successfully reproduceb. maintain homeostasisc. fight more successfullyd. evolve into a new species

EngagementEngagement

Draw two graphs on the board Draw two graphs on the board one of a direct relationship one of a direct relationship one of an inverse relationship one of an inverse relationship

In each case show a line of best fit and points In each case show a line of best fit and points that are not directly on the line.that are not directly on the line.

Can someone describe the relationship Can someone describe the relationship between variables in each graph.between variables in each graph.

EngagementEngagement

Why are there some points not directly on the Why are there some points not directly on the line?line?

Reinforce the idea of general trends that Reinforce the idea of general trends that graphs reveal.graphs reveal.

Trends of these two types are what you are Trends of these two types are what you are going to see today as you complete your quick going to see today as you complete your quick lab later in class.lab later in class.

Periodic TrendsPeriodic TrendsTrends on the Periodic Table!Trends on the Periodic Table!

Periodic TrendsPeriodic Trends

Sodium chloride (table Sodium chloride (table salt) produced the salt) produced the geometric pattern in the geometric pattern in the photograph. Such a pattern photograph. Such a pattern can be used to calculate can be used to calculate the position of nuclei in a the position of nuclei in a solid. You will learn how solid. You will learn how properties such as atomic properties such as atomic size are related to the size are related to the location of elements in the location of elements in the periodic table.periodic table.

Trends in Atomic SizeTrends in Atomic Size

The atomic radius is one half of the distance between the nuclei of two atoms of the same element when the atoms are joined.


Group and Periodic Trends in Atomic Size In general, atomic size increases from top to

bottom within a group and decreases from left to right across a period.

IonsIons

Positive and negative ions form when electrons are transferred between atoms.

Positive and negative ions form when electrons are transferred between atoms.

IonsIons

IonsIons

Some compounds are composed of particles called ions. An ion is an atom or group of atoms that has a

positive or negative charge. A cation is an ion with a positive charge. An anion is an ion with a negative charge.

Trends in Ionization EnergyTrends in Ionization Energy

The energy required to remove an electron from an atom is called ionization energy. The energy required to remove the first electron

from an atom is called the first ionization energy.

The energy required to remove an electron from an ion with a 1+ charge is called the second ionization energy.


Group and Periodic Trends in Ionization Energy First ionization energy tends to decrease from

top to bottom within a group and increase from left to right across a period.

Trends in Ionic SizeTrends in Ionic Size Trends in Ionic Size

During reactions between metals and nonmetals, metal atoms tend to lose electrons, and nonmetal atoms tend to gain electrons. The transfer has a predictable effect on the size of the ions that form.

Trends in Ionic SizeTrends in Ionic Size

Cations are always smaller than the atoms from which they form.

Anions are always larger than the atoms from which they form.


Relative Sizes of Some Atoms and IonsRelative Sizes of Some Atoms and Ions



Siz

e g

en

era

lly in

crea

ses

Trends in ElectronegativityTrends in Electronegativity Trends in Electronegativity

Electronegativity is the ability of an atom of an element to attract electrons when the atom is in a compound.

In general, electronegativity values decrease from top to bottom within a group. For representative elements, the values tend to increase from left to right across a period.

Trends in ElectronegativityTrends in Electronegativity Representative Elements in Groups 1A through 7ARepresentative Elements in Groups 1A through 7A

Summary of TrendsSummary of Trends

The trends that exist among these The trends that exist among these properties can be explained by properties can be explained by variations in atomic structure.variations in atomic structure.

Summary of TrendsSummary of TrendsAtomic Size Increases

Incr

ease

s

Decreases

Dec

reas

es

Size of cationsShieldingNuclear ChargeElectronegativityIonization energySize of anionsIonic size Constant

Short QuizShort Quiz

1.1. Which of the following sequences is correct for Which of the following sequences is correct for atomic size?atomic size?

a.a. Mg > Al > SMg > Al > S

b.b. Li > Na > KLi > Na > K

c.c. F > N > BF > N > B

d.d. F > Cl > BrF > Cl > Br


2.2. Metals tend toMetals tend to

a.a. gain electrons to form cations.gain electrons to form cations.

b.b. gain electrons to form anions.gain electrons to form anions.

c.c. lose electrons to form anions.lose electrons to form anions.

d.d. lose electrons to form cations.lose electrons to form cations.


3.3. Which of the following is the most Which of the following is the most electronegative?electronegative?

a.a. ClCl

b.b. SeSe

c.c. NaNa

d.d. II

GraphingGraphing

Graphing Physical PropertiesGraphing Physical Properties PurposePurpose

Make a graph of physical properties versus atomic Make a graph of physical properties versus atomic number and use the graph to identify periodic and group number and use the graph to identify periodic and group trends.trends.

Periodic TrendsPeriodic Trends

Periodic Trends worksheet.Periodic Trends worksheet. Review the worksheet.Review the worksheet.

Summary

Was the objective accomplished? Explain.Was the objective accomplished? Explain. How can you compare the different trends How can you compare the different trends

within the periodic table?within the periodic table? Devise a way to remember the trends of the Devise a way to remember the trends of the

periodic table.periodic table. Explain the importance of the trends of the Explain the importance of the trends of the

periodic table.periodic table.

HomeworkHomework

Study for your Atomic Structure AssessmentStudy for your Atomic Structure Assessment Take home your notebooks.Take home your notebooks.

Complete any make up work!Complete any make up work! Due next class.Due next class.

Drill Determine the group and period of the following: Determine the group and period of the...

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