Download The Periodic Table of Elements and Atom Types

The Periodic Table of
Elements and Atom Types
I. Organization of the Periodic Table
A. periodic law – properties of elements
tend to change in a regular pattern
when elements are arranged in
order of increasing atomic number.
B. Elements are arranged in periods and
groups
1. period – a horizontal row of the
elements in the periodic table
a. another name for periods are valences
2. Every atom has valence electrons
a. Electrons are arranged in energy levels.
i. Each energy level can hold only a specific
number of electrons
ii. Electrons start at the energy level closest to
the nucleus and fill up one energy level
after another.
b. valence electron – an electron
in the outermost energy
level of an atom
B. Elements are arranged in periods and
groups
1. period – a horizontal row of the
elements in the periodic table
a. Another name for periods are rows
b. Each period has a number, which refers
to how many energy levels are in that
element.
2. group (family) – a vertical column of the
elements in the periodic table
a. Groups of elements in the periodic
table, have similar properties
b. Valence electrons largely effect
chemical and physical properties.
c. Elements in the same
group have the
same number of
valence electrons.
II. Ions!!!
A. Ion – an atom that has lost or gained one
or more electrons and therefore has a net
electric charge.
E. Atoms have no overall charge
1. An un-reacted, elemental atom has the
same number of protons as electrons
2. Each proton has 1 positive charge and
each electron has 1 negative charge.
3. Positive charges and negative charges
cancel each other out.
2
7 protons =
2
7 neutrons =
+ 2
7 electrons =
+2
7
0
-2
7
0
charges
charge
charges
charge
II. Ions!!!
A. Ion – an atom that has lost or gained one
or more electrons and therefore has a net
electric charge.
B. Ionization – the
process of adding or
losing one or more
electrons from an
atom
C. Atoms want all of their energy levels to be
full.
Adding or losing electrons helps
this to happen.
C. Ions have charge!
1. cation – an ion that
has given
onecharges
or
17 protons
= up
+ 17
0 charge
more electrons 18 neutrons =
18 electrons =
- 18 charges
a. Cations have+ more
protons than
-1
charge
electrons.
b. Cations have an overall positive charge.
2. anion – an ion that has gained one or
more electrons
a. Anions have fewer
protons
11 protons
= than
+ 11 charges
12 neutrons =
0 charge
electrons.
10 overall
electronsnegative
=
- 10 charge.
charges
b. Anions have+an
+1
charge
III. Differences in atomic structure
A. Atomic number
1. atomic number – the number of protons
in an atom
2. Each element has its own atomic
number.
B. Atomic mass
1. atomic mass – the mass of an atom of
a given element
2. The average atomic mass is never a
whole number.
C. Isotopes!!
1. isotopes – any atoms
having the same number
of protons but different
numbers of neutrons
13
12
C
2. average atomic mass – the mass of the
average atom of a given element
a. Atomic mass unit (amu) – a unit
equivalent to 1/12 the mass of a carbon12 atom (~1 proton or neutron)
b. It reflects number of protons and
neutrons in naturally occurring elements.
12 protons
12 protons 12 protons
+12 neutrons +13 neutrons +14 neutrons
24 amu
25 amu
26 amu
78.65% x 24 amu
10.14% x 25 amu
+ 11.13% x 26 amu
24.305 amu
26
Mg
25
Mg
24
Mg