If you look at images of the alkali metals, you will see that many of the elements have a similar appearance.

Elements in the same family also have similar properties that can be seen. Listed below are some characteristics that the alkali metals share.

Alkali metals have the following characteristics:

• Have low ionization energies
• Form colorless cations ions, with a +1 charge
• Are reactive metals
• React with water vapor or oxygen in air
• Form water-soluble bases
• Have low densities
• Have low melting points
• Are strong reducing agents
• Are good conductors of electricity and heat
• Are ductile, malleable, and soft.

Look at the Bohr models of each of the alkali metals.

Notice that each element has one electron in the outer energy level.

Now, look at the electron configuration for each of the alkali metals.

Element	Electron Configuration
Lithium	1s22s1
Sodium	1s22s22p63s1
Potassium	1s22s22p63s23p64s1
Rubidium	1s22s22p63s23p63d104s24p65s1
Cesium	1s22s22p63s23p63d104s24p64d105s25p66s1
Francium	1s22s22p63s23p63d104s24p64d104f145s25p65d106s26p67s1

Notice that the outer most energy level of each element consists of an s sublevel with one electron.

Element	Electron Configuration
Lithium	1s22s1
Sodium	1s22s22p63s1
Potassium	1s22s22p63s23p64s1
Rubidium	1s22s22p63s23p63d104s24p65s1
Cesium	1s22s22p63s23p63d104s24p64d105s25p66s1
Francium	1s22s22p63s23p63d104s24p64d104f145s25p65d106s26p67s1

Now, let’s analyze the elements in the oxygen family. Notice the 6A at the top of the column.

If you look at images of the oxygen family, you will see that some of the elements have similar appearances.

You can see that the elements in the oxygen family have many similar characteristics.

Elements in the oxygen family

• Tend to form covalent compounds with other elements,
• Commonly exist in compounds with the -2 oxidation state, but often have other oxidation states as well, and
• Tend to exist as diatomic and polyatomic molecules, such as O₂, O₃, S₆, S₈, and Se₈.

Look at the Bohr models of each element in the oxygen family.

Notice that each element has six electrons in the outer energy level.

Now, look at the electron configuration for each of the alkali metals.

Element	Electron Configuration
Oxygen	1s22s22p4
Sulfur	1s22s22p63s23p4
Selenium	1s22s22p63s23p63d104s24p4
Tellurium	1s22s22p63s23p63d104s24p64d105s25p4
Polonium	1s22s22p63s23p63d104s24p64d104f145s25p65d106s26p4

Notice that the outermost energy level of each element consists of an s sublevel with two electrons and a p sublevel with four electrons.

Element	Electron Configuration
Oxygen	1s22s22p4
Sulfur	1s22s22p63s23p4
Selenium	1s22s22p63s23p63d104s24p4
Tellurium	1s22s22p63s23p63d104s24p64d105s25p4
Polonium	s22s22p63s23p63d104s24p64d104f145s25p65d106s26p4

The electrons found in s and p orbitals of the outer most energy level are called valence electrons. These are the electrons that are involved in bonding because they are more loosely held to the nucleus, as they are further away from the nucleus than other electrons. Valence electrons give the elements their characteristics. Since all the elements in the same group have the same number of valence electrons, they have similar characteristics.

The alkali metals have one valence electron, and the elements in the oxygen family have six valence electrons.

Element	Electron Configuration
Lithium	1s22s1
Sodium	1s22s22p63s1
Potassium	1s22s22p63s23p64s1
Rubidium	1s22s22p63s23p63d104s24p65s1
Cesium	1s22s22p63s23p63d104s24p64d105s25p66s1
Francium	1s22s22p63s23p3d104s24p64d104f145s25p65d106s26p67s1
Oxygen	1s22s22p4
Sulfur	1s22s22p63s23p4
Selenium	1s22s22p63s23p63d104s24p4
Tellurium	1s22s22p63s23p63d104s24p64d105s25p4
Polonium	s22s22p63s23p63d104s24p64d104f145s25p65d106s26p4

You’ll often need to know how many valence electrons an element has. It would be quite time consuming to list the complete electron configuration of an element every time you needed to know how many valence electrons there were in a particular element. Luckily, the periodic table tells you this information.

Earlier, it was pointed out that the alkali metals were in group 1A of the periodic table. You just learned that they have one valence electron. You also saw that the oxygen family was in group 6A on the periodic table and had six valence electrons. This matching of the group number and the number of valence electrons is not a coincidence. The group number identifies the number of valence electrons. This is very useful information!

Boron is in group 3A.

Interactive popup. Assistance may be required.

How many valence electrons does boron have? 3

What about the transition metals?

All transition metals have very similar properties. Listed below are some of the common properties of transition metals.

Transition metals have the following properties:

• Have higher melting and boiling points that metals in groups 1 and 2
• Are good conductors of heat and electricity
• Are malleable and ductile
• Have a silvery luster (except copper and gold)
• Tend to have two or more common oxidation states
• Often form colored compounds

Transition metals are more complicated because they don't always use the same number of valence electrons in chemical reactions. For example, iron sometimes gives away two electrons, and other times it gives up three electrons.