http://www.ck12.org Chapter 6. The Periodic Table
FIGURE 6.8
This periodic table shows the outer electron configurations of the elements.the alkali metal of Period 2, is 1s^22 s^1. This single valence electron is what gives the alkali metals their extreme
reactivity. Pictured below (Figure6.10) is the element, sodium.
All alkali metals are very soft and can be cut easily with a knife. Due to their high reactivity, they must be stored
under oil to prevent them from reacting with oxygen or water vapor in the air. The reactions between alkali metals
and water are particularly vigorous and include the rapid production of large quantities of hydrogen gas. Alkali
metals also react easily with most nonmetals. All of the alkali metals are far too reactive to be found in nature
in their pure elemental form. For example, all naturally occurring sodium exists as a compound, such as sodium
chloride (table salt).
The elements in Group 2 (beryllium, magnesium, calcium, strontium, barium, and radium) are called thealkaline
earth metals(Figure6.11). These elements have two valence electrons, both of which reside in the outermosts
sublevel. The general electron configuration of all alkaline earth metals isns^2. The alkaline earth metals are still too
reactive to exist in nature as free elements, but they are less reactive than the alkali metals. They tend to be harder,
stronger, and denser than the alkali metals, and they also form numerous compounds with nonmetals.
Watch videos of experiments involving thes-block elements:
- Reaction of Lithium with Water at http://www.youtube.com/watch?v=Vxqe_ZOwsHs
- Reaction of Lithium with Oxygen at http://www.youtube.com/watch?v=mXv38UvP_tQ
- Reaction of Sodium with Water at http://www.youtube.com/watch?v=dmcfsEEogxs