BLOCK:
DATE:
NAME:
ATOMS, ELEMENTS, AND THE PERIODIC TABLE
ALCHEMY
Picture
Theory/Discovery
Democritus
(460 BC)
This man came up with the theory that if
you took a stone and cut it in half you would
have two pieces with the same properties. If
you continued to do this you would
eventually reach the smallest particle, which
he named “atomos”, which means
indivisible.
Dalton
(1808)
This scientist came up with the first atomic
theory. That all matter is made of atoms,
that all atoms of a given element are
identical and that chemical reactions involve
the combination (rather than the
destruction) of atoms. He envisioned the
atom as a solid, hard ball and grouped
elements according to their atomic weight.
J.J. Thomson
(1897)
This man discovered the electron. He
imagined that an atom had chunks of
negative particles scattered throughout a
fluid smear of positive charge. This is early
atomic theory is called the “plum pudding
model”.
Rutherford
(1908)
He came up with a revolutionary view of
atomic structure thanks to his experiments
with radioactive alpha particles. He
suggested that the atom had a densely
packed nucleus of positive charges
surrounded by a ring of electrons (negative
charges).
Bohr
(1913)
This physicist studied light spectra which
allowed him to come up with the theory that
electrons can exist in different energy levels.
This is shown with different sized rings
(energy levels) of electrons orbiting an atom’s
nucleus.
Chadwick
(1932)
This man discovered the third type of
subatomic particle: the neutron. Neutrons
help to reduce the repulsion of protons,
which helps keep the nucleus stable. Unlike
protons and electrons, neutrons have no
electrical charge.
The Atom!
Summary Dalton’s Original Theory of Matter:
1.
2.
3.
4.
Current model of the atom:
Summary of Subatomic Particles
Charge
weight
symbol
Location
electrons
protons
neutrons
 Remember…
# p+ = Atomic Number
# e- = # p+
(assuming that most atoms are neutral: equal number of + and - )
3
since…
Atomic Mass =
# p+ (Atomic Number)
# n = Atomic Mass - Atomic Number
+ #n
Atomic Number
Atomic Mass
Li
Lithium
6.99
Observe the pictures of the following atoms, elements and compounds. Describe the difference
between each of those pictures that you see.
1. What is/are the difference(s) between atoms and molecules?
2. What is/are the difference(s) between elements and compounds?
3. Describe the difference(s) between the molecules of an element vs. molecules of a compound.
BOHR’S MODEL OF ATOMIC STRUCTURE
 Niels Bohr proposed that _______________ move around the _____________ of an atom in
___________ that are __________________
 Bohr created a way to ________________ the structure of atoms(now called _____________________)
 RULES FOR DRAWING BOHR DIAGRAMS:
e- orbit #
+
(a) Draw nucleus containing p and n
(b) Fill e- orbits in order from inside to outside
(c) Each e- orbit must be filled before starting to fill the next orbit
(d) Each e- orbit can only hold a specific # of e-
EXAMPLES
Lithium (Li)
Oxygen (O)
# of e- the
orbit can
hold
THE PERIODIC TABLE
Examine a periodic table…What patterns (or trends) can you identify?
Dimitri Mendeleev was one the first scientists to study
the _______________ of elements
 Mendeleev organized the elements on the periodic table
according to ______________ &_____________ that he
observed in their properties (published his first book in the
late 1860’s)
 today, many __________ of elements can be identified on
the periodic table:
(1) Metals and Non-Metals
 divided by the ____________________ line on the periodic table
 Metals to the _____________, Non-Metals to the ______________
 the properties of metals and non-metal are very different:
METALS
NON-METALS
(2) Semi-Metals (also called Metalloids)
 located along the line between the ______________ and _____________________
 includes ______, ______, ______, ______, ______, ______, and sometimes _______
 usually show both metal and non-metal characteristics
Ex) Silicon - has a ________ lustre, yet it is an inefficient _______________ and is __________
(3) Transition Metals
 found in the ______________ of the periodic table
 have typical metal properties, but also have the following properties:
(a) very ___________
(b) very high _______________ and _____________ points
(c) have _______________ combining capacities (ion charges)
(4) Periods
PERIOD
 the _________________ rows of the periodic table
 lists elements in order of increasing ______________________ and ______________________
(5) Families
 contain elements that share similar ___________________________
Alkali Metals
Alkaline Earth Metals
FAMILY
 the _____________________ columns of the periodic table
Halogens
Noble Gases
(6) Diatomic (2-atom) Molecules
 there are certain ______________ that have elements that don’t like to
N
O
F
be by themselves ()…so they find one __________________ ()
ex)
 includes _____, _____, _____, _____, _____, _____, _____, and ______
 called the “magic 7” + hydrogen. These elements form an imaginary figure 7
on the periodic table
Cl
Br
I
At