65 BIG HISTORY PROJECT
4:49–5:37
ALKALI METALS
Armed with this insight, you insert gaps into the
table and things suddenly fall perfectly into place.
Seven element periods for the first two rows with
hydrogen in its own category. 18-element periods
for the next two rows. You’re so certain, that you
predict the properties of these missing elements.
And when a French scientist comes along and
says that he has, in fact, discovered one of them,
you argue with him, saying that you discovered it
first in your mind. And when you see his data and it
doesn’t match yours, you publish a paper saying his
data for the new element he discovered is wrong.
That’s how certain you are of yourself and this
beautiful new theoretical framework you’ve created.
And you know what the really crazy thing is? You’re
right. That French guy’s data was wrong. You, never
having examined the element he discovered, knew
more about it than he did. Because you are Men-
deleev, master of the elements.
Okay, we’re done imagining for the episode. That
was fun though. The different groups Mendeleev
had identified are a lot of the same groups that we
study today. Starting at the left we have the soft,
shiny, extremely reactive alkali metals. So reactive,
in fact, that they have to be stored in inert gases
or oil to prevent them from reacting with the atmo-
sphere.
Alkali metals want nothing more than to dump off
an electron and form a positive ion or cation. And
they’re always jonesing to hook up with a hottie
from the other side of the table. So, of course, see-
ing as they’re so reactive, you don’t find hunks of
them lying around in nature.Instead, chemists must
extract them from compounds containing them.
Next you have the alkaline earth metals. Reactive
metals, but not as reactive as the alkali metals,
forming cations with two positive charges instead
of just one. Calcium, shown here undergoes a very
similar reaction to sodium in water, just a little
more slowly, producing a little less heat.
The middle body area of the table is made up of a
nice solid rectangle of transition metals. These are
the metals you think of as metals with iron, and
nickel, and gold, and platinum. The majority of ele-
ments are metals — they’re fairly unreactive, great
conductors of heat, but more importantly for us,
good conductors of electricity. They’re malleable
and can be bent, and formed, and hammered into
sheets. And they’re extremely important in chem-
istry, but overall surprisingly similar to each other.
On the far right, just over from the noble gases, the
halogens make up a set of extremely reactive gases
that form negative ions or anions with one negative
charge and love to react with the alkali and alkaline
earth metals.
5:38–6:19
ALKALINE EARTH
METALS
6:20–6:50
HALOGENS