Download Matter and the Periodic Table

What is Matter and what are the Basics?
Atom:
The basic particle of an
element.
NUCLEUS - the center or core of an atom, where the
protons and neutrons are located
PROTONS - the positively charged particles in an
atom
NEUTRONS - the neutral particles in an atom
ELECTRONS - the negatively charged particles in an
atom
VALENCE ELECTRONS - electrons that are
involved in transfer or sharing
Element:
A pure substance that cannot be broken down into any
other substance by chemical or physical means.
Atomic Mass: The atomic mass of an element is the sum
of the number of protons AND neutrons. (unit “amu”)
For example, carbon has six protons. One isotope of
carbon also has 6 neutrons. This means that its atomic
mass is 12, or 6 protons + 6 neutrons.
Another isotope of carbon has 8 neutrons. This means that
its atomic mass would be 14, or 6 protons + 8 neutrons.
Atomic Number:
The number above the symbol, 17, is the element's atomic number. The
atomic number of an element is the number of protons in each atom
of that element. For example, every atom of chlorine has 17 protons. Its
atomic number is 17.
The Periodic Table
In 1869 Dmitri Mendeleev (18341907) succeeded in organizing the 62
elements known at that time into a
system of rows and columns on the
basis of increasing mass and similar
chemical and physical properties.
Since the organization exhibited a
periodic repetition of similar
properties, it became known as the
Periodic Table of the Elements. It has
become one of modern chemistry's
most useful resources.
Mendeleev: figured out the
beginnings of the Periodic
Table! (Russian)
I knew
how to
observe
and then
infer!
Periods: the horizontal rows of the P. Table. There are 7. As
you move from left to right, properties of the elements change
according to a pattern.
Groups: Also known as families, the 18 vertical rows The
elements in each group have similar characteristics.
Each family of the periodic
table has its own
characteristic properties
based on its number of
valence electrons.
Isotope: elements having the same # of protons, BUT different
numbers of neutrons…
In this case each isotope has one
proton but a different number of
neutrons
Radioactive isotopes: an atom that has a nucleus that
gives off radiation because it is not “stable” These
isotopes are used in medicine as they are traceable as
they travel through your body.
Molecule:
Groups of two or more atoms held together
by chemical bonds.
Chemical bond:
Force of attraction between
two atoms.
Compound: A pure substance made of two or more
elements chemically combined in a set ratio.
Why is the
bucky ball not
a compound?
COVALENT BOND - a chemical bond formed when
two atoms share electrons.
IONIC BOND - the attraction between two
oppositely charged ions.
ION - an atom or group of atoms
that has become electrically
charged.
Another way of looking at “Bonds”
Chemical Reaction: A reaction in which new
substances are formed.
Chemical reactions occur when chemical bonds
break or when new bonds form.
Reactants
Products
2 H2 + O2 --> 2 H2O
reaction
What does this diagram
tell you about C, H, O, N?
1808 - John Dalton - ATOMIC THEORY
(England)
1.
Atoms can’t be broken into smaller pieces
2.
Atoms of different elements are different
3.
Atoms of two or more elements can be
combined to form compounds
4.
Atoms of each element have a unique
mass
5.
The masses of the elements in a
compound are always in a constant ratio