The Periodic Table

In this lesson…

You will be able to describe the relationship between
the arrangement of elements on the periodic table and
the properties of those elements.

The Periodic Table

The periodic table is an arrangement of the elements
in order of their atomic numbers such that elements
with similar properties fall in the same column or
group.

The Periodic Table

The information contained in each square on the
periodic table is the element’s atomic number,
chemical name, average atomic mass, and chemical
symbol.

The Periodic Table

The chemical symbol is the abbreviation for the
element’s name. For instance, He is the symbol for
helium.

The Periodic Table

The first letter of the chemical symbol is always upper
case. The next letter is always lowercase.

The Periodic Table

The chemical name is the name of the element.

The Periodic Table

The average atomic mass is the weighted average of
the masses of all of the naturally occurring isotopes
of that element.

The Periodic Table

The vertical columns of elements in the periodic table
are called groups. These elements have similar
physical and chemical properties.

The Periodic Table

Groups are sometimes called families. They have
similar properties because they have the same
number of valence electrons.

The Periodic Table

Valence electrons are electrons that are located in the outermost shell of the electron cloud. The number of valence electrons determines the reactivity of an element.

The Periodic Table

The horizontal rows of elements on the periodic table
are called periods. The physical and chemical
properties of these elements change in predictable
ways from one end of a period to the other.

The Periodic Table

For instance, elements on the right and left side of a
period are the least dense while the ones in the
middle are the most dense.

The Periodic Table

Elements are arranged in order of increasing atomic
number.

The Periodic Table

The periodic table is split, with the lanthanides and
actinides in two rows below the main table.

The Periodic Table

Both the lanthanides and the actinides are apart from
the main table and these elements have similarites in
properties and electron groupings.

The Periodic Table

Metals are shiny and conduct heat and electricity well.

The Periodic Table

Nonmetals are poor conductors of heat and electricity
and are often dull and brittle.

The Periodic Table

Metalloids have some properties of both metals and
nonmetals. They are often used to make semiconductor chips in computers.