UNIT VIII The Periodic Table and Chemical Bonding Lesson#3.
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Transcript of UNIT VIII The Periodic Table and Chemical Bonding Lesson#3.
UNIT VIIIThe Periodic Table and Chemical Bonding
Lesson#3
VIII.2 THE PERIODIC TABLE
Organized according to ATOMIC # --- Mendeleev
Periodic Law: the properties of the elements recur periodically when the elements are arranged in increasing order by their atomic numbers
A. The Modern Periodic TableIN
CREA
SIN
G R
EACT
IVIT
Y
Trends in the Periodic Table: PERIOD: is the set of all the elements in a
given row going ACROSS the table
FAMILY (group): is the set of all the elements in a given column going down the table
VIII.2 THE PERIODIC TABLE
Metals, Nonmetals, and Semiconductors:
Metals:malleable (flatten into sheets)ductileopaqueconduct electricity*solid at room temp (except.... )Lustre
*Metals conductivity decreases with an increase in temp
VIII.2 THE PERIODIC TABLE
Metals, Nonmetals, and Semiconductors:
NonmetalsAt room temperature: solid, liquid or
gaspoor conductors
Semiconductorsaka “metalloids” or “semimetals”conductivity increases with an increase
in temp
VIII.2 THE PERIODIC TABLE
VIII.2 THE PERIODIC TABLE
TRENDS:1. Properties of elements change from
metallic to nonmetallic going from left to right
VIII.2 THE PERIODIC TABLE
2. Elements become more metallic (or better metals) going down a family in the periodic table
VIII.2 THE PERIODIC TABLE
3. The size of the elements radius decreases going across a row and increases going down a family
Why does the size of the element increase going down?
Electron Shells
Each period on the periodic table represents a different electron shell
The more down you go, the more shells there are. Therefore, the larger the atom’s size will be.
As you go down the periodic table, the atoms get BIGGER
WHY DOES THE SIZE OF THE ELEMENT DECREASE GOING ACROSS? FROM LEFT TO RIGHT?
Atomic radius explained…
Going from left to right on the periodic table, the atomic number increases and the _________ charge on the nucleus increases
As you go across the periodic table, the atoms get SMALLER because….?
A. The Electronic Nature of Chemical Bonding Electrostatic Force: is a force existing as a result of
the attraction or repulsion between 2 charged particles
+ and – ATTRACT (different charges) + and + REPEL – and – REPEL
The closer the charges are, the greater the forceThe greater the charge, the greater the force
ELECTRON SHELLS
OPEN SHELL: is a shell containing less than its maximum number of electrons
CLOSED SHELL: is a shell containing its maximum number of electronsEx: noble gases
Valence Electrons: Total number of electrons in open shells that can participate in a chemical bond.
Use the periodic table to determine the number of valence electrons (for s and p orbitals)
Atom
Group
K
I
Ca
2
Ga
3
Ge
4
As
5
Se
6
Br
7
Kr
8
# of valence e-(e in outter shells)
CHLORINE AS AN EXAMPLE
Draw the valence electrons for Chlorine.
VIII.3 CHEMICAL BONDING
Valence: The number of unpaired valence electrons on the atom (COMBINING CAPACITY)
each ORBITAL holds 2 e- only dealing with s and p orbitals so the
maximum number of electrons in a shell is: _______________
only UNPAIRED electrons take part in bonding!
ex: B F
VIII.3 CHEMICAL BONDING
Going across periodic table the valence of an atom:
The valence is the combining capacity!
Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8
1 2 3 4 3 2 1 0
A few more things to know…
Ionization Energy (IE)
The minimum energy required to remove an electron from a an atom or molecule in the gaseous state.
Ca + energy → Ca2+ + 2e-
IONIZATION ENERGY
Going ACROSS the periodic table the ionization energy (IE) increases
Why?
Going DOWN the periodic table the IE decreasesWhy?
Ionization Energy
He has the GREATEST ionization energyFr has the LEAST ionization energy
HOMEWORK These are fast questions to answer, so solve
them all
Hebden p. 164 # 35-39
Hebden p. 166 # 42-45 and p. 168 # 47
Hebden p. 168 # 48-51 and p. 170 # 53-56