Download Structure of the Atom Today`s DCI

Structure of the Atom
Electrons
Protons
Neutrons
Protons and neutrons make up the nucleus (the
majority of the mass of the atom)
Electrons are located outside of the nucleus.
Electrons are located in orbitals…an orbital is a 3dimensional region of space where the probability
of finding the eletron is high.
Properties of Fundamental Particles
Particle Charge
Mass
Electron -1.6022 x
Proton
10-19
coulombs 9.109 x 10-28 g
+1.6022 x 10-19 coulombs 1.673 x 10-24 g
1.675 x 10-24 g
Neutron 0
Today’s DCI
DCI #3 distributed on today.
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Atomic Number
The number located above the element’s
symbol.
The atomic number is equal to the number of
protons for the element.
The symbol used to represent atomic number is
Z.
The atomic number is just a number.
Atomic Mass
The number located below the element’s symbol.
No units listed in the periodic table…we must
remember the units of the atomic mass are
atomic mass units.
The symbol for atomic mass units is u.
For hydrogen the atomic mass is 1.00797 u.
The mass of a hydrogen atom is 1.6736 x 10-24 g.
Atomic Mass
Too convert from atomic mass units to grams we
need a conversion.
By definition the relationship between atomic
mass units and mass in grams is defined as
1/12 of the mass, in grams, of the isotope of
carbon that contains 6 protons, 6 neutrons and
6 electrons.
1 u = 1/12 * 1.99268 x 10-23 g = 1.66057 x 10-24 g
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Atomic Mass
The mass in grams of a hydrogen atom is,
1.6736 x 10-24 g * (1 u/1.66057 x 10-24 g) = 1.0078 u
Hmmm…what is up?…if the atomic mass for the
element hydrogen is 1.00797 u how did we arrive at a
mass of 1.0078 u for hydrogen?
We much consider that there are three different isotopes
of hydrogen that contribute to the atomic mass of
hydrogen listed in the periodic table.
Relative Weighted Average Atomic Mass
Look at Weighted Average in your During Class
Inventions and Computer Lab Activities workbook.
Relative Weighted Average Atomic Mass
For hydrogen:
Symbol
Atomic Mass (u)
% Abundance
20Ne
21Ne
19.99244
20.993846
90.48
0.27
22Ne
21.991385
9.25
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Relative Weighted Average Atomic Mass
For hydrogen:
Symbol
Atomic Mass (u)
% Abundance
20Ne
21Ne
19.99244
20.993846
90.48
0.27
22Ne
21.991385
9.25
RWAAM = Σ(Relative Weight*fractional abundance)I
Relative Weighted Average Atomic Mass
For hydrogen:
Symbol
Atomic Mass (u)
% Abundance
20Ne
21Ne
19.99244
20.993846
90.48
0.27
22Ne
21.991385
9.25
RWAAM = Σ(Relative Weight*fractional abundance)I
RWAAM = (19.99244 u *0.9048 + 20.993846 u *0.0027 + 21.991385
u*0.0925)
RWAAM = 18.08916 u + 0.0566834 u + 2.03420 u
RWAAM = 20.1800434 u
Chapter 1
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Chapter 2
Metals
Nonmetals
Metalloids
Ions
cations: Na+, Ca2+, Al3+, Fe3+
anions: Cl–, O2– , N3–
Compounds
ionic: formula contains metal and a nonmetal
element
covalent: formula contains nonmetal elements
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