Ch 3 Section 3.9 – 3.11 Notes
Name:
Ch 3.9 Natural States of the Elements
Objective: To learn the natures of the common elements.
As we have noted, the matter around us consists mainly of
. Most often these
mixtures contain
, in which atoms from different elements are bound together. Most
elements are quite
. Thus we do not often find elements in nature in
However, there are notable exceptions. The
California that launched the
and
form.
nuggets found at
Rush in
in
are virtually pure elemental
. And
are often found in nearly pure form. Gold, silver, and platinum are
members of a class of metals called
because they are relatively unreactive.
Other elements that appear in nature in the uncombined state are the elements in Group 8:
,
,
,
,
. For example,
deposits with
, and
. They are called the
gas is found in uncombined form in underground
.
What are the pure elements that make up air?
,
,
What is a diatomic molecule? Give three examples of it.
Draw an atomic view of a sample of Argon gas. Oxygen gas. Nitrogen Gas.
Hydrogen is another element that forms
molecules. Where is almost all of Hydrogen
found, give an example?
The
an
of two
molecules to form two
molecules and
molecule. Note that only the grouping of the atoms changes in this process; no atoms are
or
. There must be the same
of H atoms and O atoms before and after
the process.
When Water decomposes, how many of atoms of each element are present at the start of process? At the
end?
is a member of Group 7, the
Group 7 elements contain
molecules.
purple
molecules.
is a brown
that contains
made up of
family. All the elemental forms of the
is a pale yellow gas containing
molecules.
molecules.
On what side of the periodic table are all but one of the diatomic molecules found?
Which diatomic molecule is not on that side?
is a lustrous,
How many elements are gases? List the names and formulas of those elements.
How many elements are liquids? List the names and formulas of those elements.
What state are the majority of the elements found on the periodic table? How many are that state?
Solid carbon occurs in
forms. Different forms of a given element are called
The three
of carbon are the familiar
and
only recently been discovered called
forms plus a form that has
. These elemental forms have very different
properties because of their different
.
Diamonds are also valued as
is the hardest natural substance.
.
is a rather soft material useful for
and for
locks. The rather odd name given to
structure of the
molecules of which it is composed. The
the structure of
.
comes from the
-ball-like structure looks like
domes.
Section 3.10 Ions
Objectives: To describe the formation of ions from their parent atoms, and learn to name them.
To predict which ion a given element forms by using the periodic table.
We have seen that an atom has a certain number of
in its nucleus and an equal number of
in the space around the nucleus. This results in an exact balance of
and
charges. We say that an atom is a neutral entity—it has
We can produce a charged entity, called an
one or more
, by taking a neutral atom and
. For example, a
in its nucleus and
If one of the
.
or
atom has
outside its nucleus.
is lost, there will be eleven
charges but only ten
charges. This gives an ion with a net positive one (1+) charge:
+
Na →
can represent this process as follows: In shorthand form,
=
. We
+
Cations and Anions
A positive ion, called a
is produced when one or more electrons are
atom. We have seen that sodium loses
electron to become a
lose more than one electron. For example, a
form a
from a neutral
cation. Some atoms
atom typically loses
cation: We usually represent this process as follows:
Mg →
electrons to
+
forms a 3+ cation by losing three electrons: That is
atom. Thus Na+ is called the
A cation is named using the name of the
is called the
When electrons are
ion, and
by a
is called the
atom, an ion with a
,
ion.
charge is formed. A
negatively charged ion is called an
with a
. An atom that
one extra electron forms an
charge. An example of an atom that forms a 1- anion is the
atom, which has
seventeen protons and seventeen electrons. That is,
Note that the anion formed by chlorine has
electrons but only
protons, so the net
charge is
. Unlike a cation, which is named for the parent atom, an
is named by taking the
name of the atom and
the Cl- anion produced from the
the
atom is called the
is obtained from the root of the atom name
. For example,
ion. Notice that the word
- plus the suffix –
. Other
Br + e- → Br- (
ion)
atoms that add one electron to form 1- ion include the following:
Fluorine
(
ion)
Iodine
(
ion)
Some atoms can add two
Oxygen
to form
(
anions. Examples include
and
S + 2e- →S2- (
ion)
:
ion)
It is important to recognize that ions are always formed by
electrons from an atom (to
form
). How are Ions never
) or
electrons to an atom (to form
formed?
.
It is essential to understand that isolated atoms do not form ions on their own. Most commonly, ions are
formed when
elements
with
elements.
What happens when metals and nonmetals react?
Ion Charges and the Periodic Table
How is the periodic table useful?
What type of ions do Group 1, Group 2, Group 3, Group 6, Group 7 elements form?
Note that metals
form
. This tendency to lose
characteristic of
.
form
is a
by
electrons.
Summarize the article Chemical Impact.
Section 3.11 Compounds That Contain Ions
Objective: To describe how ions combine to form neutral compounds.
Chemists have good reasons to believe that many chemical
instance, consider some of the properties of common table salt,
must be heated to about
to melt and to almost
contain
. For
(
). It
to boil (compare to water, which
boils at
). As a solid, salt will not conduct an
a very good
, but when melted it is
. Pure water will not conduct
current to flow), but when salt is
(will not allow an electric
in water, the resulting solution readily conducts
.
Chemists have come to realize that we can best explain these properties of sodium chloride (NaCl) by
picturing it as containing
and
packed together.
Draw a molecular picture of Sodium Chloride.
An electric current can travel along a metal wire because
through the wire; the moving electrons carry the
the
. In ionic substances the
carry
. Thus substances that contain ions can conduct an electric current
—the current travels by the movement of the charged
ions are
. When the solid
, the
throughout the water and can move around in the water, allowing it to conduct a
.
Thus we recognize substances that contain ions by their
very high
in
points, and they
properties. They often have
an electric current when melted or when dissolved
.
Define the term ionic compounds:
One fact very important to remember is that
.
1.
2.
And for any ionic compound,
Total charge of
+
Total charge of
Show how Sodium Chloride forms. Magnesium Chloride. Lithium Nitride.
=