-
The Middle Ages in Europe were called the "Dark Ages" because of the lack of scientific devolpment at that time.
-
Most alchemists in the Middle Ages were obsessed with trying to turn base metals, such as lead into gold. It never really worked though. In chemical reactions the atoms of elements present are rearranged. No new atoms are ever made.
-
The Renaissance was the end of the Dark Ages. Europe finally started to develop.
-
Hennig Brand discovered phosphorus in 1669
-
Hydrogen was discovered by Henry Cavendish in 1766.
-
Nitrogen was discovered by Daniel Rutherford 1772.
-
Joseph Priestly discovered oxygen in 1774 and published his findings the same year, three years before Carl Wilhelm Scheele published.
-
Chlorine was discovered in 1774 by Carl Helm Scheele.
-
Magnesium was recognized as an element by Joseph Black in 1775.
-
Magnesium was recognized as an element by Joseph Black in 1775.
-
Beryllium was discovered in 1798 by Louis Nicolas Vauquelin.
-
In the late 1800s, scientists realized that the nuclei of atoms did change! One element can change into another in a nuclear reaction, the opposite of a chemical reaction which involves electrons around the nucleus.
-
Sodium was discovered by Humphrey Davy in 1807.
-
Boron was discovered by Joseph Louis Gay-Lussac and Louis Jacques Thénard in 1808.
-
Lithium is the third element on the periodic table and it was discovered by Johan Arfvedson 1817.
-
Jöns Jacob Berzelius discovered the element Silicon in 1824.
-
Aluminium was discovered by Friedrich Wöhler in 1827.
-
Fluorine was discovered by Henri Moissan in 1866.
-
Helium was discovered in 1868 by Pierre Janssen 1868.
-
Argon was discovered by Lord Rayleigh and William Ramsay in 1894.
-
The Plum Pudding Model was invented by J.J Thompson in 1897. He came up with the atomic structure theory, where all parts of the atom are positive recharge.
-
William Ramsay and Morris Travers discovered Neon in 1898
-
In 1913, Niels Bohr organized the electrons into shells, now called orbitals.
-
Enrico Fermi was a pioneer in the search of new elements. In 1934, he suggested how it should be possible to make new elements, with atoms larger than the heaviest naturally occurring atoms of uranium.
-
In 1940, element 93 was produced. At that time, it was the end of the Second World War and due to all nuclear bombs dropped on Japan, new elements were identified.
-
Soon, other countries started using Fermi's ideas! They bombarded large atoms with neutrons, which transformed into protons in the nuclei of the target of atoms. Before 1955, they had made elements 94 - 101.
-
Because of the arguments between Russia and USA of what name ot give to the new elements found, IUPAC ( International Union of Pure and Applied Chemistry) finally interfered naming elements 94 - 101.
-
Earnest Rutherford shot alpha particles through a thin layer of gold foil and he found out three things.
1. Most of the particles went right through showing that nearly all of the atoms were empty space.
2. Some electrons bounced back at wide angles, showing that the center of an atom does have a nucleus.
3. Some electrons were bounced right back meaning showing that nearly all of the mass of the atom was at the nucleus/ center.