Electrons determine chemical behavior 2/24/14 2/24 Periodic Trends WB. 35-36 2/25 Electron...
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Transcript of Electrons determine chemical behavior 2/24/14 2/24 Periodic Trends WB. 35-36 2/25 Electron...
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.
(c) 2007 brainybetty.com ALL RIGHTS RESERVED. 42
Electron configurations-ways electrons arranged around nuclei
• Aufbau principle-each electron occupies lowest energy orbital available