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