Download Periodic Table

Science 7-7
Elements and the Periodic Table
Name __________________________________
Date ___________________________________
Looking for Patterns in the Elements
Matter is made up of about ________________________________________________
______________________________________________________________________
Some elements are very ____________________________________________________
________________________________________________________________________
Other elements are ________________________________
Others do not ____________________________________ at all.
Mendeleev
In the 1800’s, scientists began to suspect that the elements could be _________________
___________________________________
By 1869, one Russian scientist, Dmitri Mendeleev, recognized a ____________________
________________________________________________________________________
Medeleev studied the evidence, ______________________________________________
_______________________________________
Mendeleev’s Observations
One of Mendeleev’s first observations was that some elements have _________________
_________________________________________________________
For example, Flourine and chlorine, are both gases that ___________________________
if you breathe them.
Silver and copper are both __________________________________________________
Mendeleev believed that these similarities were _________________________________
__________________________________________________
To help him find the pattern, Mendeleev _______________________________________
________________________________________________________________________
He kept track of all the properties he knew about an element including _______________
Atomic Mass
Mendeleev also recorded two other important properties:
____________________________________ and ________________________________
Atomic mass of an element _________________________________________________
Atomic masses were determined by __________________________________________
________________________________________________________________________
Bonding power ___________________________________________________________
Chemical bond was determined ______________________________________________
________________________________________________________________________
The First Periodic Table
Mendeleev tried arranging his cards on elements in various way s.
He noticed that patterns appeared when the elements were ________________________
_______________________________________________________________________
He also discovered that the ___________________________________ of the elements
from lithium to fluorine ___________________________________________________.
Mendeleev discovered that arranging the elements by ____________________________
_______________________________________________________________________
He moved cards to positions where they _______________________________________
This left ___________________ blank spaces.
Mendeleev proposed that the blank spaces would be _____________________________
_________________________________________________________. He even
predicted their ________________________________________.
Periodic
In 1869, Mendeleev published the first _______________________________________
The word periodic means a ________________________________________________
In the modern periodic table, the properties of the elements _______________________
in each _______________ or ____________________________________.
Within 16 years, chemists _____________________________ all three of the missing
elements and named them __________________________________________________
Inside an Atom
Deep within every atom is a core called a ___________________________.
The model of the atom used today shows the nucleus as containing smaller particles
called ______________________________________. Outside the nucleus are other
particles, called _________________________________.
Measuring an Atom
Because atoms are so small, we cannot measure them with _____________________
__________________. Scientists created the ____________________________ to
measure the particles in atoms.
The mass of a proton or a neutron is about __________________________________
A proton has almost ____________________________________________________
which means that most of an atom’s mass is in its ____________________________
In the example, explain why the atom’s atomic mass is only 7 atomic mass units.
Electrical Charges
Protons and electrons also carry ___________________________________________
Neutrons are __________________________________________________________
Protons carry a ________________________________________________________
Electrons carry a _______________________________________________________
Electrons also _________________________________________________________
Atomic Number
Every atom of a particular element contains the _______________________________.
For example, every carbon atom contains ________ protons. Thus an element’s
_____________________________________________________________________
_____________________________________________________________________
However, the atoms of an element may vary in the number of ____________________
They contain. For example a carbon atom may have ___________________________
This means that the ______________________________________________________
For this reason, chemists now organize the periodic table according to _____________
_______________________________________________________________
The Periodic Table of Today
Although the periodic table is now arranged according to ________________________
______________________________________________________________________
It now contains more than _________________________________________________
Reading the Periodic Table
Each square of the periodic table usually includes the element’s ____________________
________________________________________________________________________
Chemical Symbol for an element usually contains _______________________________
The last entry in the square is the _____________________________________________
________________________________________________________________________
Organization of the Periodic Table
An element’s properties can be predicted from its _______________________________
________________________________________.
As you look at elements across a row or down a column, the elements’ ______________
_______________________________________________________________________
This predictability is the reason why the periodic table is so _______________________
_____________________________________________.
Groups
The main body of the periodic table is arranged into _____________________________
_______________________________________________________________________
The elements in a column are called a ___________________________. Groups are also
knows as _____________________________.
The group is given a family _________________________________________________
The elements in each group, or family, have ____________________________________
For example, in Group 1 al of the elements are __________________________________
Periods
Each horizontal row across the table is called a ___________________________.
A period contains a ________________________________________________of
elements from ___________________________________, just as a week on a calendar
has a series of different days.
Unlike the elements in a ___________________________________________________
Valence Electrons
It is the electrons that explain _______________________________________________
because _________________________________________________________________
This is not true for _____________________________________________
When an atom has two or more electrons, they may be ___________________________
____________________________ from the nucleus.
Only the electrons farthest out can be _________________________________________
Electrons involved in transfer or sharing are called _______________________________
Bonding Power
Elements may have _______________________________________________________
The number of valence electrons determines whether the electron ___________________
_______________________________________________________________________.
The number of valence electrons an element has ________________________________
________________________________________________.
Valence Electrons in Groups
Atoms that have the same number and arrangement of valence electrons have
____________________________ which is why the elements fall into a periodic pattern.
The elements in each group of the periodic table have the _________________________
_______________________________________________
For example, each of the elements in Group 1, have atoms with_______ valence electron.
In Group 18, each element except helium has atoms with_______ valence electrons.