Video Transcript
Which of the following figures
shows an alkali metal?
We’ve been given five figures
labeled from (A) to (E). An alkali metal is defined as any
metal in the leftmost group of the periodic table. The leftmost group can be referred
to as group one. In this group, atoms have one
outer-shell electron. Neither answer choice (C), (D), nor
(E) can be the answer to this question as none of them have one outer-shell
electron.
The atoms in answer choices (A) and
(B) both have one outer-shell electron and are both found in the leftmost group of
the periodic table. But only one of them is an alkali
metal. This is because all of the elements
in group one are alkali metals except for hydrogen, and answer choice (A) is a
hydrogen atom. It is clear that answer choice (A)
is a hydrogen atom as the whole atom only contains one electron. As answer choice (A) depicts a
hydrogen atom, it is not correct.
Therefore, the figure which shows
an alkali metal is answer choice (B).
