Download ATOMS, ELEMENTS, MOLECULES, and COMPOUNDS

ATOMS, ELEMENTS, MOLECULES, and COMPOUNDS
Atoms make up everything in the universe. Atoms are the smallest particles of
matter. Atoms have three parts called the subatomic particles: protons (positive),
neutrons (neutral), and electrons (negative).
• Protons have a positive charge and are located in the center of the nucleus.
• The nucleus is the center of the atom. The neutron is found in the nucleus.
Neutrons have a neutral charge. Some scientists say that neutrons have no
charge. Protons and neutrons are almost equal in mass and they make up
approximately 99% of the mass of an atom.
• Electrons are negatively charged and they are found in the orbital of the atom.
The orbital is like a cloud that is used to hold electrons found outside of the nucleus.
Different orbitals hold different amounts of electrons. The first orbital can hold 2
electrons. The second orbital can hold 8 electrons. The third orbital can hold 18
electrons. The fourth orbital can hold 32 electrons. As the amount of orbitals increase,
so do the amounts of the electrons they contain.
The orbital is where electrons are found.
The nucleus is where you can find protons and neutrons.
Specific types of atoms are called elements. The periodic table of
elements shows the different types of elements. Changing the number
protons in an atom makes the atoms act differently.
NASA uses
liquid hydrogen
to fuel its
rockets.
The
atoms
in with
t helium.
This is
a balloon
filled
•
•
•
•
The gas, hydrogen, has one proton and is very explosive.
Liquid hydrogen is used as rocket fuel.
Helium has two protons. Balloons filled with helium float.
Gold has 79 protons and is very expensive.
Lead has 82 protons and has almost no monetary value.
The atoms in these orbitals have been split and organized on a
chart called the periodic table. The periodic table is an
organized list of all elements found on Earth. Atoms have a certain amount of protons
and this determines what kind of atom it is. The atoms, which differ, are known as
elements. Each element has a number based on the number of protons that the
particular element contains. The atomic number is the number of protons in the
element. The number of protons in an element usually equals the number of electrons in
the element. The atomic mass of the element is the average mass of the protons plus
the neutrons. The mass of a proton is small. The atomic mass is the number the proton
contains and is referred to as a unit. A dialogue for this subject might go something like
this: “The proton has a mass of 1 atomic mass unit (or amu for short). The neutron has a
mass of about .9 atomic mass units and the electron has a mass of about .0001 atomic
mass units.” Most of the mass of an atom is located in the nucleus.
Fact: The
periodic
table was
invented by
a Russian
scientist
named:
Dmitri
Mendeleev.
An Example of a Periodic Table
Important periodic table rules:
1. If there are two letters for a symbol then the first letter is capitalized and
the second letter is lower case. Ex: He = Helium. The chemical symbol is
one or two letters used to represent the element’s name.
2. Not all of the element’s names match up with their symbols. For
example, the symbol for Gold is Au.
3. The number above the symbol is usually the number of protons, which is
called the atomic number.
4. If there is a number below the symbol, this is the average mass of the
atom, and it is called the atomic mass.
5. The different columns even have different names. Each column is called
a group or family. The elements in each group share physical and chemical
properties.
6. Each row of elements in the periodic table is called a period.
Combined elements are also known as molecules. Molecules are two or
more elements that are together. Molecules are the smallest particles of a
substance. Different elements exist in different ways. When there is more
A molecule
than
one atom it is a molecule. Some elements naturally appear together like
of water
oxygen, O2. When there are two atoms together, it is called a molecule. This
is when there is the smallest number of atoms and the capability of being called a
substance is still present. This can be a molecule of water H2O. In the water, there can
be 2 hydrogen atoms and 1 oxygen atom. If the oxygen atom is taken away, it would no
longer act like water; therefore, H2O is the smallest piece of water to exist.
This scientist
is pointing at a
compound.
Compounds
are different
atoms joined
together by
bonds.
Compounds are two or more different atoms
that are combined chemically. Atoms can be
joined by special processes. Some
compounds can be considered molecules,
but not all molecules can be considered
compounds. Water (H2O) has two or more
elements
elements, so it is a molecule, but it can also be
c
called a compound because it is made up of
two different elements. On the other hand,
hydrogen gas (H) is considered a molecule,
but it is not a compound because it is not made up of two different types of elements.
The lines are
the bonds
between the
atoms.
The different circles
are different atoms.
I.
Atoms are the smallest pieces of matter.
A. The center of the atom is the nucleus:
a.
Protons have a positive charge.
b.
Neutrons have a neutral charge.
B. The outer part of the atom is called the electron cloud, an orbital, or an
energy level:
a.
II.
Electrons have a negative charge.
Elements have a specific number of protons that define what characteristics that
the element have.
A. All of the elements are found on the periodic table.
a. The number of protons is called the atomic number.
b. The average mass of the protons and neutrons is the atomic mass.
c. Usually the number of protons equals the number of electrons.
III.
The Periodic Table is used to organize the elements.
A. The atomic number is equal to the number of protons.
B. The atomic mass is the average mass of protons and neutrons.
C. The different columns have different names. These are called families.
IV.
Molecules are the smallest form of a substance that are bonded together that
still have the same properties of that substance. Some examples are: O2, H2,
H2O.
V.
Compounds are two or more different atoms that are chemically combined.
A. Some compounds can be considered molecules, but not all molecules
can be considered compounds. Some examples are: H2), CO2, NH3,
C6H12O6.
ENGLISH
Atoms
Subatomic particles
Protons
Positive
Neutrons
Neutral
Electrons
Negative
Nucleus
Orbital
Periodic Table
Elements
Atomic Number
Atomic Mass
Unit
Molecules
Compounds
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