Post on 01-Jan-2016
The Periodic Table
The Periodic Table
Atomic Number (number of protons)
Symbol
Atomic Mass
Period
The Periodic Table
Groups are based on number of valence electrons (electrons in the outer shell or energy level) of each element
The Periodic TableDot Diagrams
The Periodic Table
Patterns of Valence Electrons
LithiumAtomic Number (number of protons)
Period
Symbol
Atomic Mass
Patterns of Valence Electrons
Number of Energy Levels: 2
First Energy Level: 2 Second Energy Level: 1
Lithium
Patterns of Valence Electrons
BerylliumAtomic Number (number of protons)
Symbol
Atomic MassPeriod
Patterns of Valence Electrons
Number of Energy Levels: 2
First Energy Level: 2 Second Energy Level: 2
Beryllium
Patterns of Valence Electrons
Boron
Atomic Number (number of protons)
Symbol
Atomic MassPeriod
Patterns of Valence Electrons
Boron
Number of Energy Levels: 2
First Energy Level: 2 Second Energy Level: 3
Patterns of Valence Electrons
SodiumAtomic Number (number of protons)
Symbol
Atomic Mass
Period
Patterns of Valence Electrons
Sodium Number of Energy Levels: 3
1st Energy Level: 2
2nd Energy Level: 8
3rd Energy Level: 1
Patterns of Valence Electrons
Number of Energy Levels: 4
1st Energy Level: 2
2nd Energy Level: 8
3rd Energy Level: 8
4th Energy Level: 1
Patterns of Valence Electrons
Number of Energy Levels: 5
1st Energy Level: 2
2nd Energy Level: 8
3rd Energy Level: 18
4th Energy Level: 8
5th Energy Level: 1
Patterns of Valence Electrons
Number of Energy Levels: 6
1st Energy Level: 2
2nd Energy Level: 8
3rd Energy Level: 18
4th Energy Level: 18
5th Energy Level: 8
6th Energy Level: 1
Patterns of Valence Electrons
Number of Energy Levels: 7
1st Energy Level: 2
2nd Energy Level: 8
3rd Energy Level: 18
4th Energy Level: 32
5th Energy Level: 18
6th Energy Level: 8
7th Energy Level: 1
The Periodic Table
A row of elements across the periodic table is called a Period
The atomic number increases one at a time across a period of elements
The Periodic Table
Period 2 starts with Lithium
Period 2
and continues across to Neon
The Periodic Table
The Periodic Table
Elements with the same number of valence electrons have similar properties
The Periodic Table
For example, lithium, sodium,
The Periodic Table
For example, lithium, sodium, and the rest of the elements in Group 1 are all alkali metals which are very reactive
Alkali Metals
The Periodic Table
GROUP 1
The Periodic Table
GROUP 1 Alkali Metals
1 Valence electron in outer shell. Very REACTIVE
The Periodic Table
GROUP 18
NOBEL GASES
The Periodic Table
GROUP 18
NOBEL GASES
8 Valence Electrons in outer shell. Very Stable
The Periodic Table
GROUP 17
HALOGENS
The Periodic Table
GROUP 17
HALOGENS
7 Valence Electrons in outer shell. Very Reactive
The Periodic Table
Other metals Groups 2 through 12
The Periodic Table
Most have 1, 2, or 3 Valence electrons
The Periodic Table
They react by losing electrons
The Periodic Table
Other Nonmetals (Green)
The Periodic Table
React by gaining electrons
The Periodic Table
Metalloids (Yellow)
The Periodic Table
Behave as metals or nonmetals
The Periodic Table
Can lose or share electrons
The Periodic Table
Hydrogen
The Periodic Table
Considered a nonmetal
The Periodic Table
Located above Group 1
The Periodic Table
One valence electron
The Periodic Table
Very REACTIVE
The Periodic Table
QUESTIONS?
Chemical Formulas and Names
What is a chemical formula?
Compounds can be represented by chemical formulas
Chemical Formulas and Names
A chemical formula is a combination of symbols that shows the ratio of elements in a compound.
Chemical Formulas and Names
Formulas of Ionic Compounds
MgCl2
The formula for magnesium chloride.
Chemical Formulas and Names
Formulas of Ionic Compounds
MgCl2 (Magnesium Chloride)
One Magnesium ion
Two Chloride ions
Chemical Formulas and Names
Formulas of Ionic Compounds
MgCl2
Mg
Cl
Cl
2+
1-
1-
Chemical Formulas and Names
Formulas of Ionic Compounds
NaCl
One Sodium ion
One Chloride ion
Chemical Formulas and Names
Formulas of Ionic Compounds
NaCl
Na Cl
1+
1-
Chemical Formulas and Names
Naming Ionic Compounds
The name of the positive ion comes first…
Followed by the name of the negative ion
Chemical Formulas and Names
Naming Ionic Compounds
If the negative ion is a single element the end of its name changes to -ide
MgO = Magnesium Oxide
NaCl = Sodium Chloride
Chemical Formulas and Names
Naming Ionic Compounds
If the negative ion is a polyatomic element the end of its name changes to –ate or -ite
NH4NO3 = Ammonium Nitrate
Ionic Compounds
They have opposite charges and opposite charges attract
Why do sodium and chloride ions bond together?
Ionic Compounds General Properties or Characteristics of Ionic Compounds
•High melting points•Conduct electricity when dissolved or melted
•Hard, brittle crystals
•Energy is required to break ionic bonds
Ionic Compounds
What are Ionic compounds?
Ionic compounds are compounds that consist of positive and negative compounds
Molecular Compounds
What are Molecular compounds?
Molecular compounds are compounds that contain molecules bonded with COVALENT bonds
Covalent Bonds
What is a covalent bond?
The chemical bond formed when two atoms share electrons
How Covalent Bonds Form
F F
F F
Covalent bonds usually form between atoms of nonmetals
Ionic Compounds vs Molecular Compounds
Ionic bonds usually form when a metal combines with a nonmetal
In Ionic bonding, atoms give up or gain an electron
Ionic Compounds vs Molecular Compounds
In covalent bonding, atoms share electrons
NaCl
Na Cl
1+ 1-
Ionic Compounds vs Molecular Compounds
Ionic Bonding
F F
F F
Ionic Compounds vs Molecular Compounds
Covalent Bonding
Covalent Bonds
What is a covalent bond?
The chemical bond that forms when two atoms share electrons
Covalent Bonds
O
H H
Hydrogen Atom Hydrogen Atom
Oxygen Atom
Water Molecule with two covalent bonds
Covalent Bonds
How many covalent bonds can an atom form?
Oxygen has 6 valence electrons so it can form 2 covalent bonds
O
Covalent Bonds
How many covalent bonds can an atom form?
The exception is Hydrogen which only needs two electrons to be complete
H
Covalent Bonds
How many covalent bonds can an atom form?
Each Hydrogen atom can form one bond because it only needs 2 electrons to be stable
H
Covalent Bonds
NHH
H
Hydrogen Atoms
Nitrogen Atom
Covalent Bonds
NHH
H
Ammonia molecule…
Three covalent bonds
Covalent Bonds
Double and Triple Bonds
O O
Oxygen Atom
Oxygen Atom
Covalent Bonds
Double and Triple Bonds
OO
Oxygen Molecule
Covalent Bonds
Double and Triple Bonds
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