Video Transcript
Atoms of the elements in the alkali
metal group can all form ions. What is the typical charge for ions
in this group?
This question involves elements in
the alkali metal group. An alkali metal is any element in
the leftmost group of the periodic table.
Let’s have a closer look at the
periodic table. The alkali metals can be found in
the shaded area in pink. The alkali metals are all the
elements in group one, excluding hydrogen. These six elements are the alkali
metal group. They are lithium, sodium,
potassium, rubidium, cesium, and francium.
These six metals have many
properties in common. One property is that they can all
form ions. And we must determine the charge of
these alkali metal ions. Using lithium as an example, let’s
look at how an atom of an alkali metal would form an ion. We can use this diagram of
lithium. It should be noted that this
diagram is not drawn to scale. Lithium atoms contain three
positively charged protons and three negatively charged electrons. Most lithium atoms also contain
four neutral particles called neutrons. As these particles are neutral,
they will not affect the overall charge. The charges on these oppositely
charged particles cancel each other out, resulting in an atom that is neutral
overall.
Another property that alkali metals
share is their high reactivity. When reacting, atoms of alkali
metals lose electrons. An atom of lithium would lose its
outermost electron. When this electron is lost, the
lithium atom still contains three protons but only two electrons. The atom is no longer neutral. With one proton greater than the
number of electrons, it is positively charged. This behavior occurs with all of
the alkali metals, and so they typically form ions with a one plus charge state.
We have found the answer to this
question. So, the atoms of alkali metals
typically form ions with a charge of one plus.
