Bonding - Atoms interact (with their electrons) to form compounds. Sodium Chlorine.
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Transcript of Bonding - Atoms interact (with their electrons) to form compounds. Sodium Chlorine.
2Three Kinds of Bonds:
IonicIonic
CovalentCovalent
MetallicMetallic
Metal gives up electrons to make opposites attract.
The sharing of electrons creates a strong bond.
All electrons are shared in a “sea of electrons.”
Metal (+) Nonmetal (-)
Nonmetal Nonmetal
Metal Metal
electrons
Metal
Metal
Metal
4
To understand how bonding works, we need to understand electrons.
ProtonProton
ElectronElectron
NeutronNeutron + +
Positive Charge
No Charge
Negative Charge
5
Valence ElectronsValence ElectronsThe electrons on the outer energy level of an atom
How many valence electrons do each of these have?
5
2
31
4
6
1
5
6
3
Li6.941
11
Na22.990
12
Mg24.305
19
K39.098
20
Ca40.08
16
S32.066
17
Cl35.453
18
Ar39.948
10
Ne1.0079
9
F18.998
13
Al26.982
14
Si28.086
15
P30.974
5
B10.811
6
C12.011
7
N14.007
8
O15.999
1
H1.0079
4
Be9.012
2
He4.003
2
8
8
Do you remember what the atomic number
represents?It is the number of protons &
electrons.
71
H1.0079
2
He4.003
Energy Level 12 electrons fit
Fill in the periodic table on your paper.
How many valence electrons does hydrogen have?
How many valence electrons does helium have?
8
3
Li6.941
10
Ne1.0079
9
F18.998
5
B10.811
6
C12.011
7
N14.007
8
O15.999
4
Be9.012
Energy Level 28 electrons fit:
Fill in the periodic table on your paper.
How many valence electrons do each of the elements above have?
9
11
Na22.990
12
Mg24.305
16
S32.066
17
Cl35.453
18
Ar39.948
13
Al26.982
14
Si28.086
15
P30.974
Energy Level 38 electrons fit
Fill in the periodic table on your paper.
How many valence electrons do each of the elements above have?
11
You should have noticed that each column has the same number of
valence electronsvalence electrons.This is true all the way down
the periodic table:1
2 3 4 5 6 7
8
12
But there is something you need to know about electrons and the energy levels where they live.
Some are happier than others.Some are happier than others.
You see, energy levels like to be FULL.You see, energy levels like to be FULL.
10
Ne1.0079
18
Ar39.948
2
He4.003
Which other atoms are FULL?
These are “HAPPY” atoms.These are “HAPPY” atoms.
13Everyone wants to be happy--Everyone wants to be happy--
so, all atoms try to get happy.so, all atoms try to get happy.
But alas, they cannot do it alone. They But alas, they cannot do it alone. They must find other atom friends to make must find other atom friends to make them happy.them happy.
• Someone that understands you.Someone that understands you.• One who is willing to give you what you need most -- One who is willing to give you what you need most --
a part of himself.a part of himself.
But the right kind of friend is hard to find -- if you But the right kind of friend is hard to find -- if you know what I mean.know what I mean.
14More on electrons:More on electrons:
Atoms get happy (stable) by filling up their outer shell of electrons.
Atoms with Atoms with 4 or more4 or more valence electrons valence electrons will not give them up!will not give them up!
No, and don’t ask again!
Yes, is there anything else?
Atoms with less than 4 valence electronsAtoms with less than 4 valence electrons are very generous. are very generous.
Which columns on the periodic table will NOT give away electrons?
Which columns on the periodic tablewill give away electrons?
friend in
need
Generous Friend
15
However this affects their charge…Remember normally:
# of Protons (+) = Electrons (-)
If the the blue atom gives up an electron, it If the the blue atom gives up an electron, it becomes (+). becomes (+).
If the yellow atom gives up an electron, it becomes If the yellow atom gives up an electron, it becomes (-). (-).
Even MORE about electrons:Even MORE about electrons:
Have the same
Lose -e makes +
Gain -e makes -
Generous friend helps
a friend in need.
16
Because of this, we assign a group of Because of this, we assign a group of elements elements
an an oxidation number.oxidation number. Compare this number to the Compare this number to the valence valence
electronselectrons. . 1+
2+ 3+ 4 3- 2- 1-
01
2 3 4 5 6 7
8
Write the oxidation numbersWrite the oxidation numberson your periodic table.on your periodic table.
H He
Be B C N O F
18
BondingBondingAn atom’s outer electron energy
level is filled by either exchanging or sharing electrons.
NaClNaClNHNH33
Na ClNa ClN H H H
N H H H
N HH
H
ClNa
Sodium
Chlorine
Electrons either taken or given away
++ Opposites attract
Ionic BondsMetal to Nonmetal
19
20
Sodium Chlorine
SodiumSodium ChlorideChloride
Sodium is happy at energy level 2.Sodium is happy at energy level 2.Chlorine is happy at energy level 3.Chlorine is happy at energy level 3.
Sodium gives Chlorine 1 electron.
NaClNaCl
ClNa
Ionic BondsMetal to Nonmetal
21
NNHH3 3 AmmoniaAmmonia
N HH
H
Covalentnon-metal + nonmetal
HydrogenHydrogen
HydrogenHydrogen
HydrogenHydrogen
NitrogenNitrogen
Energy le
vel HAPPY
Energy le
vel HAPPY
or sta
ble...
or sta
ble...
Electrons are shared.
22
Metallic
-e -e
-e-e-e
-e -e -e
-e
Ag+ Ag+
Ag+
Ag+
Ag+ Ag+
Ag+Ag+
Ag+-e-e
-e-e
Share in a sea of electronselectrons
met
al
met
al
met
al
241+
2+ 3+ 4 3- 2- 1-
0
Mg+2Cl-1
MgCl2
1 2
Oxidation Number Oxidation Number VariesVaries
Mg+2O-2
MgO2 2=
Fe+3 O-2
Fe2O3
2 3
When you combine atoms, you use the oxidation numbers to help you figure out the ratio.
Simply switch the oxidation number to get the correct subscript. Put the #s in lowest terms if
necessary.
26Polyatomic Compounds:Compounds that Act as a Unit
Mg+2 PO4-
3
Mg3(PO4)2
3 2
Li+2 SO4-
2
LiSO4
2 2
Fe+3 NO4-2
Fe2 (NO4)3
2 3
Charge Name Formula 1+ Ammonium NH4
+
1- Acetate C2H3O4-
1- Chlorate ClO3
1- Hydroxide OH-
1- Nitrate NO3-
2- Carbonate CO32-
2- Sulfate SO42-
3- Phosphate PO43-
Note the ( ) on multiple polyatomic ions.Note the ( ) on multiple polyatomic ions.
28Naming CompoundsNaming Compounds
Rules for naming binary (meaning 2 types of atoms) ionic compounds:
1. Write the name of the metal first.
Example: KBr
Potassium Potassium
2. Write the name of the nonmetal changing the ending to “ide.”
BromineBromineBromBromideide
30Naming CompoundsNaming Compounds
Rules for naming binary ionic compounds:
1. Write the name of the metal first.
Example: CuCl
Copper Copper
2. Write the name of the nonmetal changing the ending to “ide.”
ChlorineChlorineChlorChlorideide
3. If the metal is a “transition metal,” the oxidation number varies. Therefore, to name the compound we must put the ionic charge in parentheses. For example:
(I)
because the oxidation of chlorine is 1.
(Binary means 2 types of atoms.)
32Naming CompoundsNaming Compounds
Rules for naming polyatomic ionic compounds:
1. Write the name of the metal first.
Example: K2 SO4
Potassium Potassium
2. Write the name of the polyatomic nonmetal from the chart.
SulfateSulfate
Charge Name Formula 1+ Ammonium NH4
+
1- Acetate C2H3O4-
1- Chlorate ClO3
1- Hydroxide OH-
1- Nitrate NO3-
2- Carbonate CO32-
2- Sulfate SO42-
3- Phosphate PO43-
Polyatomic
33Naming CompoundsNaming Compounds
Rules for naming polyatomic ionic compounds:
1. Use the chart above to name the metal.
Example: NH4Cl
AmmoniumAmmonium
Ionic
Charge Name Formula 1+ Ammonium NH4
+
1- Acetate C2H3O4-
1- Chlorate ClO3
1- Hydroxide OH-
1- Nitrate NO3-
2- Carbonate CO32-
2- Sulfate SO42-
3- Phosphate PO43-
If the polyatomic ion is first, then:
2. Write the name of the nonmetal changing the ending to “ide.”
ChlorChlorideide
34
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