In 1871, Dimitri Mendeleev’s periodic table
was presented to the world, but missing many
of the 118 elements that we have today.
His ingenious design perfectly organized the
elements based on similarities in their properties,
leaving place-holders for those as of yet
undiscovered.
Each element added since then has a unique
story of scientific discovery, and to honor
women’s history month in the international
year of the periodic table, today we wanted
to share the story of two of chemistry’s
most brilliant and bold women and their paths
of elemental discovery -- because what they
brought to the table changed the world.
It all starts in 1896 when legendary scientist,
Marie Curie, had a breakthrough discovery
while studying uranium.
By using a tool called an electrometer, she
was able to detect electrical charge in the
air around a uranium sample, and later in
samples of minerals containing uranium.
The higher the concentration of uranium, the
more charged the air.
Her findings lead her to hypothesize that
radiation didn’t come from particular combinations
of elements, but rather from specific types
of atoms themselves.
She would use her electrometer to systematically
survey each element on the table, in addition
to many different minerals.
By 1897, she had concluded that Uranium and
Thorium were the only known radioactive elements
-- with uranium being the most radioactive.
While continuing her survey on minerals, she
discovered five times the radioactivity of
uranium in a sample called pitchblende, and
twice as much in another called torbernite.
This meant that there had to be another source
of radioactivity, and if her hypothesis was
correct… a new element!
Curie’s husband Pierre then abandoned his
own work on crystal symmetry to help her search
for more highly radioactive minerals.
By 1898, the duo had surveyed enough samples
to confidently pronounce the discovery of
two new elements: polonium and radium.
But predictions weren’t enough, the two
would need to isolate these elements in the
lab.
Because they exist in such small quantities
in nature, they would need tons of material
to be able to extract them in measurable quantities.
As she worked by hand with samples weighing
over forty pounds, day in and day out.
After three long years of back-breaking labor,
they were left with one decigram of radium
chloride, enough to determine an atomic weight
of 226 .
Polonium was never extracted successfully,
but only due to its relatively short half
life for the tools and techniques of the time,
but future methods would verify its existence
later on in form of polonium-210.
The duo’s work in radioactivity would earn
them a Nobel Prize in physics, but Marie would
also earn the honor of another Nobel in Chemistry
for her elemental discoveries!
Her tenacity and genius were later memorialized
with the the discovery of element 96 in 1944
which was named Curium in Marie’s honor.
Our next story starts in 1924, nearly thirty
years after Curie’s discoveries.
A German chemist named Ida Tacke began looking
at other empty slots in Mendeleev’s table
along with fellow chemist (and future husband)
Walter Noddack.
They focused their energy on two slots just
below manganese, elements 43 and 75, and approached
the two with Ida’s unique, yet intuitive
perspective.
They began studying patterns between elements
and their neighbors on the table.
Noting that manganese existed in similar abundance
in Earth’s crust to its horizontal neighbor
iron, they were able to deduce that 43 & 75
would share the same quality with their horizontal
neighbors as well.
This would meant that their best bet for finding
these missing elements was within mineral
samples that contained high concentrations
of molybdenum, tungsten, ruthenium, and osmium.
With the help of their colleague Otto Berg,
they began their search using x-ray spectroscopy,
and found success in a mineral called Norwegian
Columbite.
There, they discovered Element 75, which they
named Rhenium after the Rhine River in Ida’s
birthplace, and element 43, Masurium, named
in honor of Walter’s East German home.
After their ingenious breakthrough search,
the duo would get married, but not all would
end well in this chemical tale.
The scientific community pushed back on their
publications - so they would need to isolate
samples of their findings in the lab.
The two attempted to extract their elements
from over 1800 samples of different minerals,
but only successfully isolated Rhenium in
high enough quantities to be verified.
Even though the duo successfully identified
Masurium, they would not be the first to isolate
it in large enough quantities to confirm — eventually
another group of scientists would synthesize
it in a nuclear reaction in 1937, when it
was renamed Technetium.
Marie Curie and Ida Noddack are icons of chemistry
for their innovative genius, and their bold
accomplishments have inspired generations
of young women to grow up in pursuit of what
they love – chemistry!
Many more would follow in their periodic footsteps,
contributing newer elements in the table,
and adding to the radiant history of women
in the sciences.
Have any of you out there been inspired by
women in science?
Tell us your story down below in the comments.
Did you like this chemistry history video?
Let us know if you want more, and what chemists
in particular!
Be sure to check out our other chemistry videos
while you’re at it, and we’ll see you
next week.
