Transcript Chem weekly schedule 2-24-14 Stoll

Electrons determine chemical behavior
2/24/14
2/24 Periodic Trends WB. 35-36
2/25 Electron Configuration
WB: p 43-44 TB: 51-53 HW: TB p.56 #4 a-f
2/26 Electron Configuration WB: p. 44-47
2/27 Valence Electrons
WB: p. 48-50 HW: TB p. 66 # 4 a-f
2/28 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: 2/24/14 Objective: I can explain atomic radius,
electronegativity, and ionization energy and how they are
connected
Notes 2/24
Chemical groups – are the vertical columns
Periods- 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 3/6
Bohr 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 Ringer
1. 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 2/25
Atomic 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
3. How do the charge and mass of an electron compare to the
charge and mass of a proton?
Oxygen
Electron Configuration1s2 2s2 2p4
spdf NOTATION
for H, atomic number = 1
no. of
1
electrons
1s
sublevel
value of energy level
spdf NOTATION
for H, atomic number = 1
no. of
1
electrons
1s
sublevel
value of energy level
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 number
Atomic symbol
Atomic 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 handout
Answer 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 Trends
• Atomic and ionic size
• Ionization energy
• Electron affinity
Higher effective nuclear charge.
Electrons held more tightly
Smaller orbitals.
Electrons held more
tightly.
Atomic Size
• Size goes UP on going down a
group.
• Because electrons are added
farther from the nucleus, there is
less attraction.
• Size goes DOWN on going across
a period.
Atomic Radii
Figure 8.9
Trends in Atomic Size
See Figures 8.9 & 8.10
Radius (pm)
250
K
1st transition
series
3rd period
200
Na
2nd period
Li
150
Kr
100
Ar
Ne
50
He
0
0
5
10
15
20
Atomic Number
25
30
35
40
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)
Electron Configurations
and the Periodic Table
• 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.
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
→ O21s2 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.
Electron configurations-ways
electrons arranged around nuclei
•
Aufbau
principleeach
electron
occupies
lowest
energy
orbital
available
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