You most likely think that water as a substance that have the right to put the end fires. Yet some aspects are therefore reactive the they burn in water. In fact, they basically explode in water. An example is shownin the photograph below. Around 3 pounds of sodium were added to water, and also the an outcome was an explosive reaction. Why is sodium such a reactive element? In this section, you will discover out.

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Figure \$$\\PageIndex1\$$: salt reacting with water.

## The first Group

Sodium \$$\\left( \\ceNa \\right)\$$ is an facet in team 1 the the regular table that the elements. This group (column) that the table is presented below. It has the nonmetal hydrogen \$$\\left( \\ceH \\right)\$$ and six metals referred to as alkali metals. Aspects in the same team of the regular table have the same number of valence electrons. These are the electrons in the outer energy level the the atom that deserve to be affiliated in ubraintv-jp.comical reactions. Valence electron determine countless of the properties of one element, so facets in the same team have similar properties. Every the aspects in group 1 have actually just one valence electron. This makes them really reactive.

Figure \$$\\PageIndex2\$$: group 1 that the periodic table.

## Reactivity of group 1 Elements

Hydrogen is a an extremely reactive gas, and the alkali steels are even much more reactive. In fact, they room the most reactive steels and, in addition to the elements in group 17, room the many reactive of all elements. The reactivity the alkali metals rises from the peak to the bottom the the group, so lithium \$$\\left( \\ceLi \\right)\$$ is the least reactive alkali metal and also francium \$$\\left( \\ceFr \\right)\$$ is the many reactive. Because alkali steels are so reactive, they are discovered in nature only in combination with various other elements. They often combine with group 17 elements, i beg your pardon are an extremely \"eager\" to get an electron.

## Other properties of Alkali Metals

Besides being an extremely reactive, alkali steels share a variety of other properties:

Alkali steels are every solids in ~ room temperature. Alkali steels are low in density, and some of lock float top top water. Alkali steels are fairly soft. Some are even soft sufficient to cut with a knife, choose the salt pictured in the number below.

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api/deki/files/78133/CK12_Screenshot_6-9-4.png?revision=1&size=bestfit&width=406&height=238\" />Figure \$$\\PageIndex4\$$: Hydrogen has actually the smallest, lightest atoms of every elements. Pure hydrogen is a colorless, odorless, tasteless gas the is nontoxic yet highly flammable. Hydrogen gas exists mainly as diatomic (\"two-atom\") molecules \$$\\left( \\ceH_2 \\right)\$$, as shown above. Hydrogen is the most abundant aspect in the universe and the 3rd most abundant element on Earth, and also occurs mainly in link such together water.