Reading the Periodic Table

 

 

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:

 

 

 

 

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