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Reading the Periodic Table:

Objectives:

    1.    Explain why elements in a group have similar properties.

    2.    Identify the four blocks of the periodic table.

Key Terms:

    group    family    period    alkali metal    alkaline earth metal    halogen    noble gas    metal    nonmetal    semimetal    valence electron    abbreviated electron configuration    noble gas inner core

Web Resources:

 

Notes: (5-2)

The Periodic Table:

Our current periodic table lists 109 elements.  It is arranged according to the periodic law:
Elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic pattern.
Elements that have similar properties are arranged in groups or families - vertical columns
The horizontal rows are called periods.

(helios.augustana.edu/physics/ 301/periodic-table-fix.jpg)

Each period contains more elements than the previous one.  This has to do with the increasing energy levels (n=1, ...) of the atom.
    period 1 - 2 elements
    period 2 & 3 - 8 elements
    period 4 & 5 - 18 elements
    period 6 - 32 elements

Labeling and Naming:

There are currently 3 numbering schemes used in chemistry for the ordering of groups.

Roman - IA - VIIIA & IB-VIIIB
Arabic - 1A-2A, 3B-8B, 1B-2B, 3A-8A
Number - 1-18

Families:

1A - alkali metals
2A - alkaline earth metals
7A - halogens
8A - noble gases
4A - sometimes known as the Carbon group

Exception - Hydrogen can be better placed in group 7A.  Although, some books place it in both.

(web.buddyproject.org/.../web017/ images/periodic%20table.JPG)

Metals & Non-metals:

Metals include the areas shaded light blue and include the families 1A & 2A.  They share many characteristics.

luster (shine)
good conductors of heat and electricity
typically solid at room temperature
most are malleable and ductile

Non-metals are shaded light red in most periodic tables and form a diagonal from C-6 to Rn-86 and include all the elements of that corner including H. They share some of these characteristics.

do not possess luster
poor conductors of heat and electricity
neither malleable or ductile
many are gasses at room temperature
can be solid, semisolid, gas, or liquid (Br).  One is the hardest material on Earth

Semimetals or metalloids are shaded light light purple in most periodic tables form a diagonal from B-5 to At-85 and include all the elements Ge-32 and Sb-51.   They share some of these characteristics.

have some properties of metals and some of non-metals

Electron Configuration:

As you learned earlier, the number of protons in an atom is equal to the number of electrons in the atom if it is neutral.  The periodic table allows you to predict the bonding of an atom by allowing you to see the number of electrons in the valence orbital.  The valence orbital is the highest, outermost orbital of the atom and is the only one involved in the bonding of the atom.  Here are some hints for predicting valence electrons:

naCl1.gif (2068 bytes)

 

 

 

 

Elements of the same group (column) have the same valence electrons or configuration
s-block is group 1A & 2A
p-block is group 3A to 8A
        These are the representative elements or main group elements
d-block is group 3B to 2B (look at the periodic table above because the numbers are not sequential)
        These are the transition metals
f-block is located below the main table
        These are the inner transition metals or rare earth elements

To save space on electron configuration notation you can use the abbreviated notation by listing the inner gas core and then the valence electrons.

H        1S1
Li        [He]2s1
Na      [Ne]3s1
K        [Ar]4s1
Rb      [Kr]5s1
Cs      [Xe]6s1
 

 

Last modified: October 20, 2002