Transcript Chemistry Unit 4 Lecture-The Atom Part 1 - TLCD

Part I
Agenda
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Dalton’s Atomic Theory
Parts of the atom, locations, & charges
Atoms on the periodic table
Electron orbitals
1. All matter is made up of atoms.
2. Atoms are indestructible and cannot be broken into smaller
parts.
3. All atoms of one element are exactly alike, but they are
different from atoms of other elements.
4. Compounds are formed from combinations
of atoms infinite proportions.
The parts of an atom are:
Proton
Neutron
Electron
Protons and neutrons are located in the nucleus.
The atomic number is the number of protons in an element.
The atomic mass is the number of protons + the number of neutrons
in an element.
If the number of protons change, the element changes.
Carbon: 6P
Lithium: 3P
Electrons swirl around the nucleus in the electron cloud.
Electrons are located within levels in the electron cloud.
The levels are called orbitals.
Each orbital has a different amount of energy.
Electrons
What is an atomic orbital?
Orbitals and orbits
When the a planet moves around the sun, you can plot a definite path for it which is
called an orbit. A simple view of the atom looks similar and you may have pictured the
electrons as orbiting around the nucleus. The truth is different, and electrons in fact
inhabit regions of space known as orbitals.
Orbits and orbitals
sound similar, but they
have quite different
meanings. It is
essential that you
understand the
difference between
them.
Orbitals fill with electrons in a very specific way.
The first orbital, known as the 1s orbital, can only have up to 2
electrons in it at any time.
The second orbital, known as the 2s orbital, can have up to 8
electrons in it at any time.
The third orbital, known as the 2p orbital, can only have up to 18
electrons in it at any time.
Each orbital will increase in the number of electrons it can hold.
All levels will fill lowest energy first.
You can figure out which orbitals will be filled for each element
by knowing how many electrons the element has in its neutral
state. In its neutral state, all elements have the same number
of protons and electrons.
Use this chart to help you
figure out how to fill
electron orbitals.
Part of the
Atom
Location
Charge
Mass
Proton
Nucleus
Positive (+)
1
Neutron
Nucleus
Neutral (0)
1
Electron
Cloud
Negative (-)
~0
Atomic Number
Element Symbol
Element Name
Atomic Mass
6
C
Carbon
12.011
Neutral atoms (atoms without charges) have
the same number of protons and electrons.
Not all neutral atoms are stable in nature,
and therefore do not have an equal number
of protons and electrons.
Atomic Number is
the number of
protons in an atom.
Atomic Mass is the
number of protons +
the number of
neutrons.
80
Atomic Number
Hg
Element Symbol
Mercury
200.59
Atomic Mass
Boron
5
B
10.811
Element Name
11
22.99
Na
Sodium
Remember, each
periodic table may be
Element Name a little different. The
Atomic Number upper left is from the
poster, the upper right
Element Symbol is from your agenda,
the lower left is from
Atomic Mass
the handout.
The atomic number equals the number of protons in an atom.
atomic # = # protons
Atomic # = 11 # Protons = 11
The atomic mass, minus the atomic number, equals the number of
neutrons in an atom.
atomic mass - atomic # = # neutrons
Atomic mass = 22.99 = 23
23 - 11 = 12 = # neutrons
In a neutral atom, the number of electrons is equal to the number
of protons.
# protons = # electrons
11 protons = 11 electrons
The atomic number equals the number of protons in an atom.
atomic # = # protons
The atomic mass, minus the atomic number, equals the number of
neutrons in an atom.
atomic mass - atomic # = # neutrons
In a neutral atom, the number of electrons is equal to the number of
protons.
X
# protons = # electrons
Try:
Ne
He
#p =
#p =
#n =
#n =
#e- =
#e- =
The atomic number equals the number of protons in an atom.
atomic # = # protons
The atomic mass, minus the atomic number, equals the number of
neutrons in an atom.
atomic mass - atomic # = # neutrons
In a neutral atom, the number of electrons is equal to the number
of protons.
X
# protons = # electrons
Try:
Ne
He
#p =
10
#p =
2
#n =
10
#n =
2
#e- =
10
#e- =
2
Practice:
How many protons, neutrons, and electrons do each of the following have?
O
P=8, N=8, E=8
Na+
P=11, N=12, E=10
IP=53, N=74, E=54
Ar
P=18, N=22, E=18
C
P=6, N=6, E=6
Ca2+
P=20, N=20, E=18