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THE PERIODIC TABLE TODAY
Lesson Objective: Relate patterns in the physical
and chemical properties of the elements to their
positions in the periodic table.
THE PERIODIC TABLE


Matter has been studied for many centuries.
In the late 1800s, Dmitri Mendeleev
organized the elements into the periodic table.
He included the 63 known elements of his time.
PERIODIC TABLE IS SEPARATED BY A
STAIRCASE…
With
metals on the left of the
staircase, and non-metals on the
right.
Metalloids
(the staircase) have
both metallic and non-metallic
properties.
METALS:

Have some similarity in their chemical properties
because they all lose electrons to form positive
ions.
METALS:


Are typically shiny, malleable, flexible, and good
conductors of heat and electricity.
Almost all are solid at room temperature and
normal pressure.
NON-METALS:
NON-METALS:


Chemical properties are of non-metals are related
to the fact that they accept electrons to form
negative ions.
Non-metals have the ability to GAIN electrons.
NON-METALS:



Physically, non-metals are typically poor
conductors of heat and electricity.
Because they do not conduct electricity, the are
called insulators.
They can be solids, liquids, or gases at normal
temperature and pressure. **metals are almost
always solid at room temperature.
METALLOIDS:

The diagonal purple row of elements between the
metals and the non-metals.
EACH HORIZONTAL ROW OF THE PERIODIC
TABLE IS CALLED A PERIOD.

The period of an element is determined by the
number of energy levels that are occupied by
electrons.
PERIODS
Are numbered from 1 to 7
 Numbers of elements vary- first period has 2
elements; 2 & 3 have 8; 4 & 5 have 18.

Patterns:
 Moving from left to right: change from metals to
non-metals.
 Most reactive metals start on the left- as you
move to the right they become less reactive.

EACH VERTICAL COLUMN OF THE PERIODIC
TABLE IS A GROUP, OR FAMILY.
ALL THE MEMBERS OF A CHEMICAL GROUP
HAVE SIMILAR CHEMICAL PROPERTIES.

They react with the same elements in similar
ways.
Numbered from 1-18 and are usually referred to
by the first element in the column.
 E.g. Group 10 is the nickel group because nickel
is the first element at the top of that column.

HYDROGEN!


Is considered to be a unique element and in some
periodic tables it is places in a separate spot
away from other elements.
It forms compounds with almost every other
element in the periodic table.
GROUP 1- THE ALKALI METALS


All have one valence electron and are all highly
reactive metals.
Valence electrons lie in the outermost electron
shell of an element. The number of valence
electrons that an atom has determines the kinds
of chemical bonds that it can form.
GROUP 2, THE ALKALINE-EARTH
METALS- NOT AS REACTIVE AS 1

Can all combine by ionic bonding with two atoms
of Group 17 (BeCl2, MgCl2, CaCL2, etc.).
GROUP 17, HALOGENS

Group 17, the most reactive non-metals, are
called the halogens.
GROUP 18, THE NOBLE GASSES

Do not have any unpaired electrons in their
valence energy levels.
 They
are inert (stable and nonreactive under defined
circumstances), and do not react to
form compounds under normal
circumstances.
NOBLE GASSES
THE PERIODIC TABLE PROVIDES
INFORMATION FOR EACH ELEMENT.
THE PERIODIC TABLE PROVIDES
INFORMATION FOR EACH ELEMENT.
8
(atomic number-protons)
charge)
O
(symbol)
Oxygen (name)
16
(atomic mass)
2- (ion
ON THE P.A.T.



Atomic mass… 15.99 instead of 16 or 12.01
instead of 12
May give you additional information, such as
Boiling Point, K; Melting Point, K; Density,
g/cm2
Atomic mass: the mass of an atom of a chemical
element expressed in atomic mass units (amu). It
is approximately equivalent to the number of
protons and neutrons in the atom (the mass
number).
CARBON-12




Not all carbon atoms are carbon-12
1% of carbon atoms have 7 neutrons. Mass
number of these is 13.
One more naturally occurring form of carbon
atom and its mass number is 14.
How would you find out how many neutrons it
has?
CARBON 14

Is present in nature in very low concentrations.

That’s good! Carbon 14 is radioactive.


This means the atom is unstable and falls apart
easily in a nuclear reaction, releasing energy.
Carbon-14 is present in small amounts in all
living things. Scientists use it to find the age of
biological materials such as animal fossils. This
technique is called carbon dating.
SCIENTISTS CONTINUE TO ORGANIZE THE
ELEMENTS IN DIFFERENT WAYS.

E.g. Three-dimensional or continuous form.
CHECK & REFLECT
 Page
134 #1, 2, 3, 4, 5 &7