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.