Download Atomic Structure

Atomic Structure
• The smallest part of an element is an
_____________________
• All atoms consist of subatomic particles:
– ________________
– ________________
– ________________
Nucleus
• The ___________of the atom
• Contains ______________________of the
atom
• ____________ and ____________ are
found ______ the nucleus of an atom
Mass Number =___________________________
Protons
• _________________________________
• __________________________________
• 1 proton = 1 atomic mass unit (amu)
# protons = ________________________
Neutron
• _______________________________
• Found in the _______________
• 1 neutron = 1 amu
# neutrons = ____________________________
Electrons
• __________________________________
• Found in the ____________________
• Electrons have a very small mass, so we
don’t even count it!
• Electrons give atoms their
_______________________________
• Atoms are neutral so;
__________________________________
Shorthand Notation
Isotopes
• Atoms of the _________________with
________________________________.
• Nuclear symbol:
Mass #
12
Atomic #
6
C
• Hyphen notation: ______________
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Isotopes
+
Electrons
Nucleus
+
+
Neutron
+ + +
Proton
Proton
Nucleus
+
Carbon-12
Neutrons
Protons
Electrons
Nucleus
+
+
+
Neutron
+
Electrons
+
Carbon-14
Neutrons
Protons
Electrons
Nucleus
6Li
7Li
_p+
_n0
_ p+
_n0
2e– 1e–
2e– 1e–
Neutron
Electrons +
Nucleus
+
+
Nucleus
Lithium-6
Neutrons
Protons
Electrons
Proton
Neutron
Electrons +
Nucleus
+
+
Nucleus
Lithium-7
Neutrons
Protons
Electrons
Proton
17
Cl
Isotopes
37
• Chlorine-37
– atomic #:
– mass #:
– # of protons:
– # of electrons:
– # of neutrons:
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
37
17
Cl
Average Atomic Mass
• weighted _________ of all ________
• on the Periodic Table
• round to _________ decimal places
Avg.
(mass)(%) + (mass)(%)
Atomic =
100
Mass
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Calculating Average Atomic Mass
You will be given the ____________and the
____________________(how common
the isotope is in nature) of the isotope
Average Atomic Mass
• EX: Calculate the avg. atomic mass of oxygen if its
abundance in nature is 99.76% 16O, 0.04% 17O, and
0.20% 18O.
Avg.
Atomic =
Mass
=
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Example
• Carbon has 6 protons and 6 neutrons,
what is Carbon’s mass number?
• An isotope of Carbon has 6 protons and 8
neutrons, what is carbon’s mass number?
Remember the number of __________
NEVER changes for an element!
Example
• Carbon has 6 protons and 6 neutrons,
what is Carbon’s mass number?
C-12
• An isotope of Carbon has 6 protons and 8
neutrons, what is carbon’s mass number?
C-14
Remember the number of protons NEVER
changes for an element!
Isotope Review
• Same element different number of
__________________
• Different _________________
• Same _____________, therefore the
same number of protons and electrons
Atomic Structure
• ATOMS
– Differ by number of _____________
• IONS
– Differ by number of _____________
• ISOTOPES
– Differ by number of _____________
Electrons
• Electrons give elements their
__________________________________
• The arrangement of the electrons will
determine how it _________ with other
substances
• Gain electron the atom becomes _______
(_______________)
• Lose an electron the atom becomes
___________ (________________)
Electrons are found in the
______________
The cloud has regions of space called
energy levels
• The first energy level holds ____ electrons
• The second energy level holds _____
electrons.
• The third energy level holds ____
electrons
Valence Electrons
• Are found _______________________
• Dictate the _________ and ___________
________________ of an element
• Use the periodic table to determine the
number of valence electrons.
Lewis Dot Diagram
• A way to illustrate the number of valence
electrons
– Use _______for each valence electron
– Place the dot ______ each side of the symbol
before pairing the electrons
– The __________ represents the nucleus plus
all the inner electrons for the element.
Examples
H
O
N
F
Ne
Electrons and Light
• Electrons are normally in the
______________________________
• When the atom is given ___________ the
electrons move to the ___________ state.
• When the electrons ________ this energy
they fall back to the ground state and emit
_______________.
• Each element has a unique
___________________________
Electromagnetic Spectrum
• Electromagnetic Radiation –
– A broad range of energetic emissions
– made up of photons
• Photons – bundles of energy
– Travel like waves
– Move at the speed of light = 3.0 x 108 m/s
– Electromagnetic waves do not require a
medium to move
Parts of the wave
• Amplitude – the height of the wave
• Wavelength – the distance between the
two successive waves
• Frequency – the number of waves that
pass a given reference point per second
• Wavelength = lamda in units of nm
• Frequency = nu in units of 1/s or s-1
What is the difference between
these waves?