Elements and the Periodic
Table
Chapter 17
Organizing the Elements
MENDELEEV’S ORDER

Dmitri Mendeleev

Trying to organize the 63 known elements so they
were easier to understand
Organizing the Elements
MENDELEEV’S ORDER: Didn’t yet know about
protons, neutrons and electrons, ONLY MASS..
What could he do?
Organizing the Elements
MENDELEEV’S ORDER: Increasing Atomic Mass

Elements with similar properties were put in
the same column
Organizing the Elements

Named “Periodic Table” because properties
repeated ‘periodically’ from row to row.

Like keys on a keyboard (octaves)
The Modern Periodic Table
The Periodic Law

Once protons were discovered, what were
elements organized by?
The Modern Periodic Table

Increasing Atomic Number.
The Modern Periodic Table

Properties were STILL grouped by column.
The Modern Periodic Table

So, Properties STILL repeated periodically
(within a row).
The Modern Periodic Table

Like Cards in a deck:
The Modern Periodic Table
In the Modern table a PERIOD = a ROW.

How many PERIODS are there?
7
The Modern Periodic Table
PERIODS = ROWS

How many ELEMENTS are in PERIODS 1, 2, & 3?

What does this remind you of?
The Modern Periodic Table
Numbers of electrons in each ENERGY LEVEL
The Modern Periodic Table
In the Modern Periodic table a COLUMN = a GROUP

ELEMENTS within a GROUP have similar
PROPERTIES.
The Modern Periodic Table
COLUMNS = GROUPS

Therefore, properties repeat PREDICTABLY
and PERIODICALLY.
The Modern Periodic Table

THIS IS CALLED PERIODIC LAW.
The Modern Periodic Table
There are 4 important pieces of information for
each element
Atomic number
Element symbol
Element name
Atomic mass
The Modern Periodic Table
CLASSES OF ELEMENTS:
2.
State: solid, liquid, gas
Natural & manmade: (91 of the first 92 are
natural)
3.
METALS, NONMETALS & METALLOIDS
1.
The Modern Periodic Table
Properties????
What happens to properties when you move from left to right across the table?
Representative Groups
“A” GROUPS
GROUPS
Elements in groups have SIMILAR (not identical)
PROPERTIES because they have the SAME
NUMBER OF VALENCE ELECTRONS
Journal
1.
Color in the Blank Periodic Table
according to the following KEY.
Be sure to use a different color for each of the items below.



METALS
NONMETALS
METALLOIDS