Intro to Chemistry
9.29.15
• Chemistry: The study of
• Chemistry: The study of matter
• Matter:
• Chemistry: The study of matter
• Matter: Anything with mass that
takes up space
The Atom
• Atom: Smallest differentiable unit of
matter
–Composed of
The Atom
• Atom: Smallest differentiable unit of
matter
–Composed of protons, neutrons, and
electrons
Subatomic Particles
• Neutron:
–Found in the
Subatomic Particles
• Neutron:
–Found in the nucleus
–Charge of
Subatomic Particles
• Neutron:
–Found in the nucleus
–Charge of 0
–Mass of
Subatomic Particles
• Neutron:
abbr?
–Found in the nucleus
–Charge of 0
–Mass of 1 amu (atomic mass unit)
Subatomic Particles
• Neutron: n0
–Found in the nucleus
–Charge of 0
–Mass of 1 amu (atomic mass unit)
Subatomic Particles
• Proton:
–Found in
Subatomic Particles
• Proton:
–Found in the nucleus
–Charge of
Subatomic Particles
• Proton:
–Found in the nucleus
–Charge of +1
–Mass of
Subatomic Particles
• Proton:
–Found in the nucleus
–Charge of +1
–Mass of 1 amu
Subatomic Particles
• Proton: p+
–Found in the nucleus
–Charge of +1
–Mass of 1 amu
Subatomic Particles
• Electron:
–Found
Subatomic Particles
• Electron:
–Found orbiting the nucleus at a great
distance
–Charge of
Subatomic Particles
• Electron:
–Found orbiting the nucleus at a great
distance
–Charge of -1
–Mass of
Subatomic Particles
• Electron:
–Found orbiting the nucleus at a great
distance
–Charge of -1
–Mass of 0 amu (not actually zero, but
mass is so small that it is ignored)
Subatomic Particles
• Electron: e–Found orbiting the nucleus at a great
distance
–Charge of -1
–Mass of 0 amu (not actually zero, but
mass is so small that it is ignored)
Electron Orbitals
• Electrons orbit the nucleus in
discrete orbits or “shells”
–First orbital holds
Electron Orbitals
• Electrons orbit the nucleus in
discreet orbits or “shells”
–First orbital holds 2 e–2nd =
Electron Orbitals
• Electrons orbit the nucleus in
discreet orbits or “shells”
–First orbital holds 2 e–2nd = 8 e–3rd = 8 e–4th = 10 e-
Electron Orbitals
• Electrons orbit the nucleus in
discreet orbits or “shells”
–First orbital holds 2 eImportant: The valence
–2nd = 8 eelectrons (outer
rd
–3 = 8 e
shell)
are
the
only
–4th = 10 eimportant ones for
forming bonds with
other atoms
S
13
Al
Aluminum
26.982
2
8
3
S
13
Al
Aluminum
26.982
2
8
3
S
Element
Symbol
13
Al
Aluminum
26.982
2
8
3
S
Element
Symbol
13
2
8
3
Al
Aluminum
26.982
Element
Name
S
Element
Symbol
13
2
8
3
# of p+
(Atomic
Number)
Al
Aluminum
26.982
Element
Name
S
Element
Symbol
13
2
8
3
# of p+
(Atomic
Number)
Al
Aluminum
Element
Name
26.982
Average atomic mass (# of p+ + n0)
S
Element
Symbol
13
Al
Aluminum
2
8
3
# of p+
(Atomic
Number)
# of e- in
each shell
Element
Name
26.982
Average atomic mass (# of p+ + n0)
Physical state
at STP (0o @
sea level)
Element
Symbol
S
13
Al
Aluminum
2
8
3
# of p+
(Atomic
Number)
# of e- in
each shell
Element
Name
26.982
Average atomic mass (# of p+ + n0)
Models of the Atom
• Lewis dot structure: Shows the chemical
symbol and only the valence electrons (# in
outer shell)
Models of the Atom
• Lewis dot structure: Shows the chemical
symbol and only the valence electrons (# in
outer shell)
Mg
Models of the Atom
• Lewis dot structure: Shows the chemical
symbol and only the valence electrons (# in
outer shell)
B
O
Bohr Diagram
• Shows complete e- configuration (sometimes
shows details of nucleus)
• Ex: Mg
Bohr Diagram
• Shows complete e- configuration (sometimes
shows details of nucleus)
• Try: F and Ca
Isotopes
• Isotope: An atom with a different #
of n0 than normal, which therefore
also has a different
Isotopes
• Isotope: An atom with a different #
of n0 than normal, which therefore
also has a different atomic mass
Isotopes
• Ex: C-12
–p+ =
vs.
C-14
p+ =
Isotopes
• Ex: C-12
–p+ = 6
–n0 =
vs.
C-14
p+ = 6
n0 =
Isotopes
• Ex: C-12
–p+ = 6
–n0 = 6
–e- =
vs.
C-14
p+ = 6
n0 = 8
e- =
Isotopes
• Ex: C-12
–p+ = 6
–n0 = 6
–e- = 6
vs.
C-14
p+ = 6
n0 = 8
e- = 6
–Isotopes only differ in their mass, not
in their charge or their bonding
behavior