Electrons determine chemical behavior2/24/14

2/24 Periodic Trends WB. 35-362/25 Electron Configuration

WB: p 43-44 TB: 51-53 HW: TB p.56 #4 a-f2/26 Electron Configuration WB: p. 44-472/27 Valence Electrons

WB: p. 48-50 HW: TB p. 66 # 4 a-f2/28 Valence Electrons TB p. 51-53/ quiz

Date: 2/24/14 Objective: I can explain atomic radius, electronegativity, and ionization energy and how they are connected.

Bell Ringer: 1.Define ionization energy.2.Why is the 2nd ionization energy higher than

the 1st ionization energy?

Date: 2/24/14 Objective: I can explain atomic radius, electronegativity, and ionization energy and how they are connected.

Take out your note book

Title :Notes 3/6

Date: 2/24/14Objective: I can explain atomic radius, electronegativity, and ionization energy and how they are connected

Notes 2/24Chemical groups – are the vertical columnsPeriods- are the horizontal rows

As we move from left to right in a period, the ionization energy increases As we move up a chemical group, the ionization energy increases

Bohr Models of atoms are drawings of atoms that identify the proton and neutrons in the nucleus and electrons in their energy levels (shell and orbits).

Notes 3/6Bohr Models of atoms are drawings of

atoms that identify the proton and neutrons in the nucleus and electrons in their energy levels (orbits).

What atom? Draw K

Date: 2-25-14 Objective: I can relate the position of elements on the periodic table with their electron arrangement.

Bell Ringer1. Which pair of elements has the most similar

chemical properties? – Cl and Ar -K and N- Li and Na -C and Ca

2. Draw a Bohr Model of an Aluminum atom

Bohr Model of Atoms

Notes 2/25Atomic Radius is the distance from the

center of the atom to its furthest energy level.

Atomic Radius

Date: 3-11-13 Objective: I can relate the position of elements on the periodic table with their electron arrangement.Bell Ringer

4. What is the total number of electrons in an atom of an element with an atomic number of 18 and a mass number of 40?

5. Which substance can be broken down by a chemical change? – Na -NH3 -K - Mg

• How do the charge and mass of an electron compare to the charge and mass of a proton?

Oxygen

Electron Configuration1s2 2s2 2p4

11s

value of energy level

sublevel

no. ofelectrons

spdf NOTATION

for H, atomic number = 1

11s

value of energy level

sublevel

no. ofelectrons

spdf NOTATION

for H, atomic number = 1

Outer electron configuration for the elements

Date: 2-26-14 Objective: I can relate the position of elements on the periodic table with their electron arrangement and their distance from the nearest noble gas.

Fill in the blank periodic table

Label each element 1- 36 Atomic numberAtomic symbolAtomic mass

Date: 3-12-13 Objective: I can relate the position of elements on the periodic table with their electron arrangement and their distance from the nearest noble gas.

Workbook page 44-45

Complete page 44-45 #2-3a with your shoulder partner. Partner A completes information for one element and Partner B completes information for the next element. When you both finish, share your answers. Then go on to the next two elements using the same process.

Date: 3-12-13 Objective: I can relate the position of elements on the periodic table with their electron arrangement and their distance from the nearest noble gas.Class discussion about p. 44-45

Next, complete page 46-47 #3b-4c with your shoulder partner. Partner A completes information for one element and Partner B completes information for the next element. When you both finish, share your answers. Then go on to the next two elements using the same process.

Date: 3-12-13 Objective: I can relate the position of elements on the periodic table with their electron arrangement and their distance from the nearest noble gas.Class discussion about p. 46-47

Next, complete page 48-49 #4d-5h with your shoulder partner. Partner A completes information for one element and Partner B completes information for the next element. When you both finish, share your answers. Then go on to the next two elements using the same process.

Date: 3-13-13 Objective: I can assign valence numbers to elements and organize the periodic table to valence numbers

Bell Ringer- ACT practice handoutAnswer questions #14-17 on your bell ringer sheet

Date: 3-13-13 Objective: I can assign valence numbers to elements and organize the periodic table to valence numbers

Class discussion about p. 46-47

Next, complete page 48-49 #4d-5h with your shoulder partner. Partner A completes information for one element and Partner B completes information for the next element. When you both finish, share your answers. Then go on to the next two elements using the same process.

Date: 3-13-13 Objective: I can assign valence numbers to elements and organize the periodic table to valence numbers

Read workbook page 51-52 and take cornell notes

Date: 3-15-13 Objective: I can assign valence numbers to elements and organize the periodic table to valence numbers

Bell ringer Write the electron configuration and draw the Bohr model for Fluorine

General Periodic TrendsGeneral Periodic Trends• Atomic and ionic sizeAtomic and ionic size• Ionization energyIonization energy• Electron affinityElectron affinity

Higher effective nuclear charge.Electrons held more tightly

Smaller orbitals.Electrons held moretightly.

Atomic SizeAtomic SizeAtomic SizeAtomic Size

• Size goes UPSize goes UP on going down a on going down a group.group.

• Because electrons are added Because electrons are added farther from the nucleus, there is farther from the nucleus, there is less attraction.less attraction.

• Size goes DOWNSize goes DOWN on going across on going across a period.a period.

• Size goes UPSize goes UP on going down a on going down a group.group.

• Because electrons are added Because electrons are added farther from the nucleus, there is farther from the nucleus, there is less attraction.less attraction.

• Size goes DOWNSize goes DOWN on going across on going across a period.a period.

Atomic RadiiAtomic RadiiAtomic RadiiAtomic Radii

Figure 8.9Figure 8.9

Trends in Atomic SizeTrends in Atomic SizeSee Figures 8.9 & 8.10See Figures 8.9 & 8.10

0

50

100

150

200

250

0 5 10 15 20 25 30 35 40

Li

Na

K

Kr

He

NeAr

2nd period

3rd period 1st transitionseries

Radius (pm)

Atomic Number

0

50

100

150

200

250

0 5 10 15 20 25 30 35 40

Li

Na

K

Kr

He

NeAr

2nd period

3rd period 1st transitionseries

Radius (pm)

Atomic Number

Electron Configurations• The electron configuration of an atom is a

shorthand method of writing the location of electrons by sublevel.

• The sublevel is written followed by a superscript with the number of electrons in the sublevel.

– If the 2p sublevel contains 2 electrons, it is written 2p2

Writing Electron Configurations• First, determine how many electrons are in the

atom. Iron has 26 electrons.

• Arrange the energy sublevels according to increasing energy:

–1s 2s 2p 3s 3p 4s 3d …

• Fill each sublevel with electrons until you have used all the electrons in the atom:

–Fe: 1s2 2s2 2p6 3s2 3p6 4s2 3d 6

• The sum of the superscripts equals the atomic number of iron (26)

• The periodic table can be used as a guide for electron configurations.

• The period number is the value of n.• Groups 1A and 2A have the s-orbital filled.• Groups 3A - 8A have the p-orbital filled.• Groups 3B - 2B have the d-orbital filled.• The lanthanides and actinides have the f-orbital filled.

Electron Configurations Electron Configurations and the Periodic Tableand the Periodic Table

Valence Electrons• When an atom undergoes a chemical reaction,

only the outermost electrons are involved.

• These electrons are of the highest energy and are furthest away from the nucleus. These are the valence electrons.

• The valence electrons are the s and p electrons beyond the noble gas core.

Predicting Valence Electrons• The Roman numeral in the American convention

indicates the number of valence electrons.

– Group IA elements have 1 valence electron

– Group VA elements have 5 valence electrons

• When using the IUPAC designations for group numbers, the last digit indicates the number of valence electrons.

– Group 14 elements have 4 valence electrons

– Group 2 elements have 2 valence electrons

Electron Dot Formulas• An electron dot formula of an elements shows the

symbol of the element surrounded by its valence electrons.

• We use one dot for each valence electron.

• Consider phosphorous, P, which has 5 valence electrons. Here is the method for writing the electron dot formula.

Ionic Charge• Recall, that atoms lose or gain electrons to form

ions.

• The charge of an ion is related to the number of valence electrons on the atom.

• Group IA/1 metals lose their one valence electron to form 1+ ions.

– Na → Na+ + e-

• Metals lose their valence electrons to form ions.

Predicting Ionic Charge• Group IA/1 metals form 1+ ions, group IIA/2

metals form 2+ ions, group IIIA/13 metals form 3+ ions, and group IVA/14 metals from 4+ ions.

• By losing their valence electrons, they achieve a noble gas configuration.

• Similarly, nonmetals can gain electrons to achieve a noble gas configuration.

• Group VA/15 elements form -3 ions, group VIA/16 elements form -2 ions, and group VIIA/17 elements form -1 ions.

Ion Electron Configurations• When we write the electron configuration of a

positive ion, we remove one electron for each positive charge:

Na → Na+

1s2 2s2 2p6 3s1 → 1s2 2s2 2p6

• When we write the electron configuration of a negative ion, we add one electron for each negative charge:

O → O2-

1s2 2s2 2p4 → 1s2 2s2 2p6

Conclusions Continued

• We can Write the electron configuration of an element based on its position on the periodic table.

• Valence electrons are the outermost electrons and are involved in chemical reactions.

• We can write electron dot formulas for elements which indicate the number of valence electrons.

Conclusions Continued• We can predict the charge on the ion of an

element from its position on the periodic table.

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Electron configurations-ways electrons arranged around nuclei

• Aufbau principle-each electron occupies lowest energy orbital available