VALENCE ELECTRONS-the
outermost electrons
located in the highest
energy level
A. WRITE THE NOBLE GAS CONFIGURATION
B.IDENTIFY THE NUMBER OF VALENCE
ELECTRONS
ELEMENT
1.Tin
2. Chlorine
3.Radium
4.Rubidium
5.Lead
SYMBOL
Sn
Cl
Ra
Rb
Pb
ATOMIC NO.
50
17
88
37
82
ILLUSTRATE THE IONIC
BONDS OF THE FF. ATOMS
1. Mg and Cl
2.Na and O
3.Al and S
Ionic and covalent compounds
differ in their properties
because the particles in each
of these two compounds are
held together by different
types of chemical bonds.
In an ionic compound, the alternate positiv
and negative ions in an ionic solid are
arranged in an orderly way to form a giant
ionic lattice structure with ionic bond
between the ions. The ionic bond is the
strong electrical attraction (electrostatic
force) between the positive and negative
ions next to each other in the lattice.
The strong bonding force makes ionic compounds
to have high melting and boiling points. All ionic
compounds are hard but brittle crystalline solids at
room temperature. Many, ionic compounds (but
not all) are soluble in water. The solid crystals DO
NOT conduct electricity because the ions are not
free to move to carry an electric current. However,
if the ionic compound is melted or dissolved in
water, the liquid will now conduct electricity, as
the ion particles are now free to move.
Most covalent compounds are
made up of independent
molecular units with relatively
weak attraction forces between molecules
The intermolecular force between the covalent compounds is very
weak.Therefore, covalent compounds have low melting and boiling
point. They are also poor conductors of electricity because there are
no free electrons or ions in any state to carry electric charge. They may
exist as solid, liquid or gas.
Organic Chemistry-chemistry of virtually all carbon
compounds
Organic Compounds-characterized by carbon hydrogen bonds which
are not found in inorganic compounds
-have lower melting and boiling points and are
flammable compared to inorganic
-have covalent compounds
-contain long and complex chains of molecules
HYDROCARBONS-organic compounds that contain
only carbon and hydrogen
ALKANES-simplest hydrocarbons which contain only single covalent
bonds CnH2n+2
ALKENES-contain carbon-carbon double bond CnH2n
ALKYNES-contain carbon-carbon triple bond CnH2n-2
Prefix: meth-1 C
pent- 5 C
non- 9 C
eth-2 C
hex- 6 C
dec- 10 C
prop-3 C
hept- 7 C
but- 4 C
oct- 8 C
example:
ethane
CH3
CH3
ethene
CH2
CH2
ethyne
CH
CH
Properties
Alkanes-nonpolar;very weak van der Waals forces
-not attracted to water
oil(hyrdocarbon) do not mix with water
“like dissolve like”
Hydrocarbons of low molar mass tend to be gases or low-boiling
liquids
• UNSATURATED COMPOUNDS
contain double or triple carboncarbon bonds
• SATURATED COMPOUNDS
alkanes (which contain maximum
number of hydrogens)