Download PPT

Essential Principles of
Chemistry
Lecture 3
Generalized Atomic Structure

Nucleus houses the massive
particles (protons and neutrons)




# Protons = Atomic Number
# Protons + Neutrons = Atomic Mass
Responsible for mass and density
Electrons lie in orbitals that
surround the nucleus


# Electrons = # Protons
 If not, then it is an ION
Responsible for bonding
Ions

Ions are electrically charged particles formed by
the gain or loss of electrons


Cations are positively charged
Anions are negatively charged

Metals are elements that readily form cations

Non-Metals are elements that readily form
anions
Electron Orbitals
Alkali Metals
Alkali Earth Metals
Transition Metals
Metaloids
Other Metals
Non-Metals
Halogens
Noble Gases
Decreasing Atomic Radius
Decreasing Atomic Radius
Electronegativity: measure of an atom’s
ability to attract electrons in a chemical bond
Ionic Bonds

An atom with lower
electro negativity
transfers one or more
electrons to an atom with
higher electronegativity
 Metal with non-metal

Results in charged ions

Oppositely charged ions
are attracted and thereby
form a weak bond
Ionic Bonds

Ions are not actually
“attached” and so bonds
are relatively weak
 Soft minerals

Ions can be attracted by
other charged ions or
molecules
 Soluble in water
Covalent Bonds

Two atoms with
approximately equal
electronegativity share
one or more electrons

Results in a merging of
the electron clouds, and
thereby forms a strong
bond
 Hard minerals
Metallic Bonds

Delocalized sharing of
free electrons among a
lattice of metal atoms
with little or no difference
in electronegativity

Results in one continuous
electron cloud
 Soft, malleable
minerals that conduct
both heat and
electricity
Natural Bonds Usually Share
Characteristics
Van der Waal’s “Bonds”

Attraction between
atoms, ions or molecules
that have an imbalance in
the distribution of
electrons (dipole)

Fleeting and fluctuating
weak attractions
 Soft minerals with a
low melting point
 Allows for the basal
cleavage in micas