Warm Up- Complete the tableWarm Up- Complete the table

Atom Neutrons Protons Electrons Charge

Al-26 10

Ca-40 2+

P-29 0

How does Al-26 differ from Al-27?How does Al-26 differ from Al-27?

How does an atom differ from an ion?How does an atom differ from an ion?

How did you do?How did you do?

Atom Neutrons Protons Electrons Charge

Al-26 13 13 10 3+

Ca-40 20 20 18 2+

P-29 14 15 15 0

How does Al-26 differ from Al-27?How does Al-26 differ from Al-27?

How does an atom differ from an ion?How does an atom differ from an ion?

As we think about why the trends occur…. We As we think about why the trends occur…. We need to remember what we know about need to remember what we know about

Coulombic attraction.Coulombic attraction.

1.1.What is a coulombic attraction?What is a coulombic attraction?

2.2.What did you notice about the attractive force What did you notice about the attractive force going down a group?going down a group?

3.3.Is the attractive force of the nucleus divided up Is the attractive force of the nucleus divided up among the electrons or does each electron get the among the electrons or does each electron get the full force?full force?

4.4.What happens to the attractive force going What happens to the attractive force going across a period? Why?across a period? Why?

Work on the Trends ActivityWork on the Trends Activity

If you finish answering all the questions and If you finish answering all the questions and identify the trends. Give some thought to identify the trends. Give some thought to explaining the trends.explaining the trends.

25 minutes???25 minutes???

Chemical PeriodicityChemical PeriodicityChapter 5 Chapter 5

Periodic Trends in Atomic SizePeriodic Trends in Atomic SizePeriodic Trends in Ionization Periodic Trends in Ionization

EnergyEnergyPeriodic Trends in Ionic SizePeriodic Trends in Ionic SizePeriodic Trends in Periodic Trends in

ElectronegativityElectronegativity

Periodic Trends in Atomic SizePeriodic Trends in Atomic Size

The boundary of an atom can't The boundary of an atom can't be measured directly be measured directly

Atomic Radius: half the distance Atomic Radius: half the distance between nuclei of two like between nuclei of two like atoms.atoms.

Draw the Bohr model for Draw the Bohr model for Li, K and FLi, K and F

Look at the position of these elements on the Look at the position of these elements on the Periodic Table. Can you detect a Periodic Table. Can you detect a ““trendtrend”” in size in size

as you go down a group?as you go down a group?

What is the trend is going What is the trend is going across a period?across a period?

Does this align with what you saw in the activity?Does this align with what you saw in the activity?

Explain the trend in your own words!Explain the trend in your own words!

Atomic size increases down a groupAtomic size increases down a group– What happens to the energy level as we go What happens to the energy level as we go

down a group? Where are the electrons?down a group? Where are the electrons?

Atomic size decreases from left to rightAtomic size decreases from left to right– Where are the electrons? Where are the electrons? – the nucleus has more attraction to the electronsthe nucleus has more attraction to the electrons

Periodic Trends in Atomic SizePeriodic Trends in Atomic Size

Which would be Which would be bigger?bigger?

a. Sodium or Aluminuma. Sodium or Aluminum

b. Magnesium or Bariumb. Magnesium or Barium

c. Nickel or Brominec. Nickel or Bromine

d. Calcium or Yttriumd. Calcium or Yttrium

e. Describe in your own words why e. Describe in your own words why atoms in the same period decrease in size atoms in the same period decrease in size from left to right.from left to right.

Was there a trend in Was there a trend in Melting Point?Melting Point?

file:///Users/teacher/Desktop/Melting%20point%20trend

Periodic Trends in Ionization Periodic Trends in Ionization EnergyEnergy

Ionization Energy:Ionization Energy:– Energy required to Energy required to

overcome the attraction of overcome the attraction of the nucleus and remove anthe nucleus and remove an electron.electron.

Write the EC for Write the EC for Li, Na and N and FLi, Na and N and F

Explain the trend in ionization energy!Explain the trend in ionization energy!

Write the EC for Write the EC for Li, Na and N and FLi, Na and N and F

Ionization energy decreases as you move down Ionization energy decreases as you move down a group because electrons are further away so a group because electrons are further away so they are easier to strip off.they are easier to strip off.

Ionization energy increases as you move left to Ionization energy increases as you move left to right, for representative elements because the right, for representative elements because the attraction by the nucleus is stronger so it is attraction by the nucleus is stronger so it is harder to pull electrons away.harder to pull electrons away.

Warm UpWarm Up

The density of bone is 1.85 g/cmThe density of bone is 1.85 g/cm33. If your . If your pinky finger has a mass of 20.0g, what is it’s pinky finger has a mass of 20.0g, what is it’s volume?volume?

Would your pinky bone sink or float? Would your pinky bone sink or float?

Look at theLook at theTable of Ionization EnergiesTable of Ionization Energies

First ionization energy- energy necessary to First ionization energy- energy necessary to remove the 1remove the 1stst electron electron

Second ionization energy- energy necessary Second ionization energy- energy necessary to remove the 2nd electron.to remove the 2nd electron.

Third ionization energy- energy necessary to Third ionization energy- energy necessary to remove the 3remove the 3rdrd electron. electron.

How does becoming an ion How does becoming an ion affect the size of the atom?affect the size of the atom?

Periodic Trends in Ionic SizePeriodic Trends in Ionic Size

LetLet’’s look at Li and F again.s look at Li and F again.

If each atom wants to achieve a full outer If each atom wants to achieve a full outer energy level (full octet)…. What has to energy level (full octet)…. What has to happen to the electrons?happen to the electrons?

When they gain or lose electrons, what do When they gain or lose electrons, what do they become? they become?

What happens to the size of the atom?What happens to the size of the atom?

Periodic Trends in Ionic SizePeriodic Trends in Ionic Size

Anions are atoms that have gained electrons Anions are atoms that have gained electrons and have an overall negative charge.and have an overall negative charge.

Anions are larger than the atoms from which Anions are larger than the atoms from which they have formed.they have formed.

Why?Why?

Cations are atoms that have lost an Cations are atoms that have lost an electron and have an overall positive electron and have an overall positive charge.charge.

Cations are smaller than the atom from Cations are smaller than the atom from which they have formed. which they have formed.

Check it out!Check it out!

Periodic Trends in Ionic SizePeriodic Trends in Ionic Size

Cations decrease in the size from left to right.

Anions decrease in size from left to right

As you move down a group the radius increases because of more electrons in higher energy levels

Which atom is the largest?Which atom is the largest?

Mg or MgMg or Mg2+2+

O or OO or O2-2-

CuCu2+2+ or Cu or Cu4+4+

Write a rule that will help you get Write a rule that will help you get

these right every time!these right every time!

IsoelectronicIsoelectronic

NaNa1+1+, Ne and F, Ne and F1-1- are said to be are said to be IsoelectronicIsoelectronic..

a. Determine the electron configuration for a. Determine the electron configuration for each of the atomseach of the atoms

b. Db. Define isoelectronicefine isoelectronic

IsoelectronicIsoelectronic

1.1. Write a 2- ion that is isoelectronic with MgWrite a 2- ion that is isoelectronic with Mg2+2+

2.2. Write 3 ions that are isoelectronic with KrWrite 3 ions that are isoelectronic with Kr

3.3. Write 2 ions that are isoelectonic with NiWrite 2 ions that are isoelectonic with Ni

Trends in ElectronegativityTrends in Electronegativity

Electronegativity:Electronegativity:

– The tendency of an element to attract The tendency of an element to attract electrons when in a chemical bond.electrons when in a chemical bond.

LetLet’’s look at Li, Cs and Fs look at Li, Cs and F

LetLet’’s look at your table of s look at your table of electronegativities.electronegativities.

Electronegativity table:Electronegativity table:– Noble gases are left out because they Noble gases are left out because they do do

notnot form compounds. form compounds.– Metals have low electronegativity numbers Metals have low electronegativity numbers

because they want to give electrons away, because they want to give electrons away, not attract them.not attract them.

– Nonmetals have high electronegativity Nonmetals have high electronegativity numbers because they attract electrons to numbers because they attract electrons to make their make their configurations more configurations more stablestable

Trends in ElectronegativityTrends in Electronegativity

Element ReactivityElement Reactivity

What would make an element reactive?What would make an element reactive?Which elements are most reactive?Which elements are most reactive?

What would make an element unreactive?What would make an element unreactive?Which elements would be most Which elements would be most unreactive?unreactive?

VideoVideo

Metal Reactivity ClipMetal Reactivity Clip

http://www.youtube.com/watch?http://www.youtube.com/watch?v=m55kgyApYrYv=m55kgyApYrY

Warm Up: In CBWarm Up: In CB

Which is more electronegative? Use the Which is more electronegative? Use the trend, then check them using the table.trend, then check them using the table.

Al or Cl?Al or Cl?

Ca or Ba?Ca or Ba?

Ga or SGa or S

I or Cl?I or Cl?

W or Zn?W or Zn?

What is Nuclear Shielding?What is Nuclear Shielding?

Nuclear Shielding is the phenomenon that Nuclear Shielding is the phenomenon that occurs that helps also helpsexplain some of occurs that helps also helpsexplain some of the trends.the trends.

Draw the Bohr Model for Phosphorus.Draw the Bohr Model for Phosphorus.

Which electrons are feeling the full Which electrons are feeling the full

effect of the nucleus?effect of the nucleus?

SheildingSheilding

Inner shell electrons “shield” the nucleus.Inner shell electrons “shield” the nucleus.

This allows for electron, electron repulsion to This allows for electron, electron repulsion to have a greater effect on the atom.have a greater effect on the atom.

Warm Up- Fill in the following table Warm Up- Fill in the following table (p.159 may help)(p.159 may help)

AtomAtom Metal or Metal or nonmetal?nonmetal?

Stable ionStable ion Size relative Size relative to neutral to neutral

atomatom

Larger or Larger or smaller than smaller than

SS2-2-

PP

RbRb

ClCl

BeBe

AlAl

How did you do?How did you do?

AtomAtom Metal or Metal or nonmetal?nonmetal?

Stable ionStable ion Size relative Size relative to neutral to neutral

atomatom

Larger or Larger or smaller than smaller than

SS2-2-

PP nmnm PP3-3- largerlarger largerlarger

RbRb mm RbRb1+1+ smallersmaller smallersmaller

ClCl nmnm ClCl1-1- largerlarger smallersmaller

BeBe mm BeBe2+2+ smallersmaller smallersmaller

AlAl mm AlAl3+3+ smallersmaller smallersmaller