Everybody remembers trying to learn the periodic table in science lessons at school. The table is one of the fundamental building blocks of chemistry, explaining the relationship between different chemicals and how they react. The modern periodic table was arranged by Russian chemist Dmitri Mendeleev in 1869 and is a tabular arrangement of the chemical elements using columns and rows, according to their chemical and physical properties.
Who was Dmitri Mendeleev?
Dmitri Mendeleev was born in February 1834 in a village near Tobolsk in Siberia and was believed to be the youngest of 17 siblings, although that number is not certain.
Aged 16, the young Dmitri moved to Saint Petersburg where he trained to become a teacher.
He later awarded for a master’s degree in chemistry at the university in 1856.
Mendeleev was interested in formulating the known chemical elements into a identifiable system and he was not the only one.
At this time, other chemists were beginning to put together the foundations of a periodic table which would group together chemical elements with similar properties.
Mendeleev’s predecessors included John Newlines who listed the elements in arrangements of eight, which he likened to octaves in music.
An alternative structure was Otto Benfey’s periodic table in 1960, which listed the elements in a continuous spiral.
In 1867, Mendeleev wrote two definitive volumes of Principles of Chemistry which would give him his breakthrough in organising the periodic table.
His idea was to leave space for the elements that were yet to be discovered.
He arranged the elements in order of increasing relative atomic mass in vertical columns to show a periodic trend.
And doing this he was able to even predict some of the gaps that would later be confirmed.
He did this by working out the atomic mass of the missing elements, which he would use to estimate how they would behave.
One example of this success was the undiscovered element, later called gallium, which ended up being close to his predictions of how it would behave.
He even swapped some of the order of the elements if they fitted their properties better.
His initial layout of rows was switched to columns in 1871, outlining the element’s oxidation state and by the 1930s, his ideas were being used in scientific textbooks.