Download UNIT_6___ELECTRON___CONFIGURATIONS__NOTES

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ELECTRON CONFIGURATIONS
Shells: ( Quantum #’s ) ( Energy Levels)
Are distinct energy levels in which electrons may be
found.
NOTE: As the shells are further away from the nucleus, the
greater the energy of the electrons)
e-
P+N0
shells 1 – 7 ( electrons in 7 have the most energy)
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Orbitals: Within each shell, electrons are found traveling in
a distinct path that draws out a specific shape
4 orbital types: s p d f
NOTE: Each orbital can hold up to 2es = spherical shape ( there is 1 s orbital
p = figure 8 shape ( there are 3 p orbitals
d = figure 8 with halos
f = general craziness
Each new shell starts with an s orbital and goes up from there.
Subshells: are just a designation of which energy level and
what orbital type the electrons are found in.
Ex. 1s = 1st shell and spherical orbital type
3p = 3rd shell and figure 8 orbital type
Shells: designated by 1,2,3,4,5,6,7
Orbitals designated by letters s,p,d,f
Subshells designated number and letter 3p
S orbital always fills first before p orbitals and each p
orbital will pick up one electron before they fill
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ELECTRON CONFIGURATION: tells the specific orbitals
and shells that all of an elements electrons are found in.
Example:
Hydrogen Z= 1
Z stands for atomic number which = the
number of protons and thus the number of
electrons in an atom of an element.
Electron configurations
Hydrogen Z=1 1s1
Helium Z=2 1s2
Lithium Z= 3
Oxygen Z= 8 so…
1s22s1
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s (l=0)
p (l=1)
d (l=2)
f (l=3)
n=
1
n=
2
n=
3
n=
4
n=
5
...
n=
6
n=
7
...
...
...
...
...
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LEWIS STRUCTURES:
An abbreviated method to show how many outershell ean atom has.
Covalent bonds:
Chemical bonding in which outer shell e- are shared
between atoms in order to fulfill the octet rule.
- Hydrogen only forms covalent
- Carbon compounds form covalent
- Non-metals will form covalent w/ other nonmetals
Ionic bonds:
-Chemical bonding where outershell e- are
transferred from one atom to another in order
to fulfill the octet rule.
-Alkali and Alkaline earth metals only form ionic
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CHEMICAL BONDING:
2 types
a. Covalent bonding:
Electrons are shared between
atoms in order to get 8e- in
outer shell
b. Ionic bonding:
Electrons are transferred from
one atom to another.
IONIC BONDING: transfer of e9p+
10n0
3p+4No
Li
+
F ------- LiF
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COVALENT BONDING : SHARING OF e9p+
10no
9p+
10no
ISOTOPES:
Atoms of the same element with different numbers of
Neutrons
Isotopes equal proton number
C,
C
Isotones equal neutron number
C,
N
Nuclide: The elements found on the periodic table with
masses and atomic numbers listed. If they have
any different #s of neutrons than they are
isotopes.
Nucleon: The subatomic particles that are found in the
Nucleus
Atomic number: (Z ) Represents the number of protons
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in the nucleus. Defines the element.
Atomic mass: (A) ( mass number) ( molar mass)
The sum of the protons and neutrons in the
nucleus of an atom.
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C
Sample Problem:
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C
13
C
An atom of a given element has A= 56 . There are 25
neutrons in the nucleus. The atom has a -1 charge on it.
a.
b.
c.
d.
e.
What is this element?
What is Z
What is A
How many protons does it have in the nucleus?
How many electrons are present?
IONIZATION ENERGY AND ELECTRON AFFINITY:
These two factors have a huge impact on why certain
elements are more reactive than others.
The Alkali metals and alkaline earth metals become more
reactive as you move down the family. Why?
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ELECTRON AFFINITY:
This is the attraction an atom has for electrons.
Which would have a higher electron affinity?
metals or non-metals? Why?
IONIZATION ENERGY:
This is the energy needed to bump the most loosely held
electron off the outer shell of an atom.
Which would have a higher ionization energy
Metals or nonmetals? Why?
THREE FACTORS EFFECTING IONIZATION ENERGY.
1. Nuclear Charge:
(+) The greater the nuclear charge the higher the
ionization energy.
2. Shielding Effect
The inner e- tend to lower ionization energy because
they shield the outer shell e- from the (+ ) nuclear
charge.
3. Radius of the atom:
The further away the outer shell e- the lower the
ionization energy.
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-radii decrease across a period because of increasing Z.
-radii increase down a group because of the increasing
distance of the electrons from the nucleus.
- increasing distance from the nucleus outweighs effective
nuclear charge for atomic radii down a group.
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ELECTROMAGNETIC SPECTRUM
The spectrum of energy consisting of alternating electric
and magnetic waves.
It consists of all wavelengths dealing with
Longest to shortest wavelength : λ - greek letter lambda
Electric - radio- microwaves- ir- roygbiv- uv- xray- gamma- cosmic
Longest ----------------------------------------------------------shortest
All travels at the speed of light ( c ) in a vacuum
Emission Spectrum:
The unique set of electromagnetic radiation given off by a
substance when electrons are pushed to a higher energy
level
Absorption Spectrum:
The unique set of electromagnetic radiation that is
absorbed when a gaseous substance has white light shone
on it.
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Emission spectrum of iron
Emission spectrum of hydrogen
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Octet Rule:
All atoms try to get 8 electrons in the
outer shell to be chemically stable.
- Note: One exception to this rule :
 The 1st shell can only hold 2eFAMILIES OF ELEMENTS:
Vertical Columns on the periodic table
Elements with similar chemical properties are
called chemical families
( because they have the same # e- in the outer
shell)
PERIODS OF ELEMENTS:
Horizontal rows with elements that have the
same number of electron shells
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IA Alkali metals: 1e- in outer shell
- Most reactive metal family
- All metals
- Not found as free elements in nature
- Oxidation # +1
- NaCl salt, NaF - toothpaste,
- K (potassium in bananas electrolytes)
- Solids @ room temp
IIA Alkaline earth metals 2e- in outer shell
- Second most reactive family of metals
- Not found as a free element in nature
- Ba, Mg, Sr, Ca
- Oxidation # +2
- Uses BaSO4 – Xrays, CaO2 - glass
- All solids @ room temp
IIIA Boron Family 3e- in outer shell
- Metals and nonmetals
- Oxidation # +3
- B, Al,
- All Solids @ room temp
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- Found as free elements
- Aluminum used in cans, roofs etc
- Not highly reactive
IVA Carbon Family (4e- in outer shell)
- Metals and nonmetals
- C, Pb, Sn
- All solids
- Not highly reactive family
- Found as free elements
- Uses lead batteries, xray , tin cans , carbon
used everywhere. Greater than 90% of
compounds on earth are made of carbon
VA Nitrogen Family: (5e- in outershell)
- Gases and solids
- Metals , nonmetals
- Not highly reactive: found as free elements
VI Oxygen Family (6e- in outer shell)
- Gases and solids
- Metals and nonmetals
- Not highly reactive
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- O, S, Polonium
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Na
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K
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VII
-
Halogen Family (7e- in outer shell)
Halogen means salt producing
Not found as free elements in nature
Fluorine is the most reactive element of all
All poisonous
All nonmetals
Solids, liquids, gases
Highly reactive
F, Cl, Br, I
Flourine used in toothpaste, Chlorine used in
Pools, Iodine used on cuts (Why?)
VIII Noble Gases ( inert gases) Inert = nonreactive
- All gases
- Nonreactive (inert)