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 yetundiscovered.
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, themore charged the air.
Her findings lead her to hypothesize
that radiation didn’t come from particular combinations
of elements, but rather from specific typesof 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 weightof 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
for 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 them
with Ida’s unique, yet intuitive perspective.
They began studying patterns between elements and their neighbors on the table.
Noting that manganese existed in a similar abundance
与它同一行的相邻元素 铁 差不多
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
含有钼 钨 钌和锇的矿石标本中
samples that contained high concentrationsof 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 womenin 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?
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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.