Download Atoms and the Periodic Table

Atoms and the Periodic
Table
Atom
The smallest unit of an element
 Atoms are made of even smaller
subatomic particles: protons, neutrons,
and electrons.
 Protons carry a positive charge, electrons
carry a negative charge and neutrons are
neutral!

Charges
An atom is neutral when the number of
protons is equal to the number of
electrons.
 An ion is a charged atom!
 A positively charged atom is called a
Cation – it has more protons than
electrons
 A negatively charged atom is called an
Anion – it has more electrons than
protons.

Periods


Periods go left to right. There are 7 periods in
total.
Elements have something in common if they are
in the same period. All of the elements in a
period have the same number of atomic orbital's.
Every element in the top row (the first period)
has one orbital for its electrons.
Hydrogen is
from
period 1 and
has one orbital.
Potassium is
from period 4
and has 4
orbital's.
Groups
These are the vertical columns on a
periodic table. There are 18 columns
which are called groups or families.
 Excluding the transition metals, each
element in a group has the same number
of electrons in the outer shell.

Families

Elements in the same family have similar
properties, some examples are:
EXAMPLES OF PHYSICAL
PROPERTIES
- Density
- Boiling Point
- Melting Heat Capacity
-State of matter at room
temperature
EXAMPLES OF CHEMICAL
PROPERTIES
- Combustibility
- Reactivity
- Radioactivity
EXAMPLES OF FAMILIES
- Alkali Metals
- Alkaline Earth Metals
- Transition Metals
- Basic metals
- Metalloid
- Non Metals
- Halogen Gases
- Noble Gases
- Lanthanide Series
- Actinide Series
Reading the Periodic Table
Atomic Number
 The number of protons in an
atom identifies the element
and the atomic number .
Atomic Symbol:
 The atomic symbol is one or
two letters chosen to
represent an element ("H"
for "hydrogen," etc.).
Reading the Periodic Table
Atomic Mass



The atomic mass is the
average mass of an element
in atomic mass units ("amu").
To calculate the mass you
add the total protons and
neutrons.
Electrons have such little
mass that they are not even
factored in the equation.