Where did it come from? Was is created or discovered?

What is the Periodic Law Mendeleev, a Russian Chemist, was one of the first to be partially successful in arranging the known elements in the 1870's into a chart that would allow the prediction of properties. He arranged the elements known in those days according to increasing atomic masses. The first Periodic Law proposed by him stated: The properties of the elements are a periodic function of their atomic masses" The 1 st of three milestones in the creation of the Modern Day Periodic Table started with Dimitri Mendeleev.

The History of the Table Antoine LavoisierIn 1789 Antoine Lavoisier first defined a chemical element & drew up a table of 33 elements. He grouped these elements into 4 groups – Metals – Non-metals – Earths – Gases

The History of the Table 1829  Johann Dobereiner Law of Triads He observed that, in a set of three elements whose chemical properties were similar, the atomic weight of the second member of the "triad" was almost exactly the mean of the atomic weights of the first and third elements Triad LithiumLi Sulfur Sulfur SChlorineCl SodiumNaSeleniumSeBromineBr PotassiumK Tellurium Te IodineI

The History of the Table 1858 Cannizzaro1858 Cannizzaro Developed a method for calculating Atomic masses of elements. This agreed upon method eliminated the need for equivalent weights in which each element had many possibilities de Chancourtois1862 de Chancourtois Became the 1 st to show the connection between atomic weights and periodicity. Using oxygen(16) as a standard of comparison, he drew the elements in a continuous spiral. This aligned the Triads & was called the TELLURIC SCREW

The History of the Table 1865 John Newlands1865 John Newlands Created a table of seven columns and entered his elements in increasing atomic masses. Due to misalignments he squeezed some elements into the same box. Law of OctavesHe called this arrangement the Law of Octaves. Every 8 th element would repeat properties repeat properties Li BeBCNOF NaMg Al SiPS Cl K Cr/Mn & Fe Co/NiCu/Zn Se AsBr

The History of the Table 1869 Mendeleev discovered not designed the basis for the modern periodic table Mendeleev discovered not designed the basis for the modern periodic table. When Mendeleev arranged the known elements using his periodic law, he found that certain elements grouped themselves into vertical groupings. He used the chemical and physical property periodicity and atomic mass of the elements to organize the elements. Mendeleev Genius was attributed to the fact he left gaps for undiscovered elements. He predicted the properties of the eka-aluminum (Gallium),eka-boron(Scandium) and eka-silicon (Germanium)

Sir William Ramsay With the discovery of He and Ar a new group had to be created. Ramsay proposed a new group to fit between group 17 and group 1 by 1900 the nobel gases were discovered, defined and placed into the periodic table.

The History of the Table In 1914 using X-rays Moseley determined the Atomic # of 38 known metals. In 1914 using X-rays Moseley determined the Atomic # of 38 known metals. Moseley then proceeded to rearrange the elements according to increasing atomic numbers. Moseley's arrangement seemed to clear up the contradictions of Mendeleev periodic table based on increasing atomic weights. ( Ex: Ar-K, Co-Ni, Te-I …) Moseley's periodic law is now considered the Modern Periodic Law. “ The properties of the elements are a periodic functions of their atomic numbers" The 2 nd of three milestones in the creation of the Modern Day Periodic Table continued with Henry Moseley.

The History of the Table There are two special series of elements that occur right after the transition metal element Actinium (Actinides) and Lanthanum(Lathanides). These special inner transition state metals were first rearranged by Dr. Glen Seaborg in the 1950's. It caused quite a stir until it was pointed out and demonstrated that this arrangement seemed to predict the properties of several newly synthesized man-made elements. Dr. Seaborg's work is the third milestone in our quest to make order out of the elements Glen Seaborg Proposed a change.

The Modern Periodic Table Metals Atoms that tend to lose their valence shell e- during a chemical Change LaLa AcAc

The Modern Periodic Table Non-metals Elements which tend to have their atoms gaining electrons during chemical change LaLa AcAc

The Modern Periodic Table Metalloids Elements which tend to have their atoms sometimes losing and sometimes gaining electrons during chemical change. These elements are generally found touching the Stairstep line LaLa AcAc

The Modern Periodic Table The Noble gases Elements that belong to their own category since their atoms tend neither to lose nor gain electrons. These elements maintain a Stable octet of Valence e LaLa AcAc

The Modern Periodic Table The Representative elements (Groups 1,2,13,14,15,16,17,18) These Elements follow general trends. The properties that are observed have their basis in the periodicity exhibited by the elements LaLa AcAc

The Modern Periodic Table The Transitional Metals Elements which include Seaborg’s Lanthanide and Actinide series follow many of the same trends with a few exceptions. Such as; ionic radii changes as they lose d shell e’ LaLa AcAc

Mendeleev He was born in Russia in 1834, Hard work as a youth opened up the college doors. He always tried to be the best that he could be, And chose to make his mark in chemistry.

Mendeleev Who told the elements where to go? MENDELEEV! Who put them in columns and in rows? MENDELEEV! Who was ready who was able to make a periodic table? Who was that chemist? MENDELEEV!

Mendeleev He wondered if Nature really had a master plan, If the elements had a pattern that one could understand, So he bought a bunch of cards and on each one wrote the name, Of an element and its weight, and then he played the game. He put them all in order by their atomic weights, Used their chemical properties to differentiate. Groups began to form & despite some question marks, He managed to produce a simple periodic chart.

Mendeleev Who told the elements where to go? MENDELEEV! Who put them in columns and in rows? MENDELEEV! Who was ready who was able to make a periodic table? Who was that chemist? MENDELEEV!

Mendeleev At first in 1869 the chart was not a hit, But that young Russian chemist was not the kind to quit. He revised atomic weights and staked his whole career, Predicting that several new elements would appear. A few years passed and sure enough they came, Gallium, Scandium, Germanium were their names. Chemist everywhere were impressed with what they saw, There really must be something to that periodic law.

Mendeleev Who told the elements where to go? MENDELEEV! Who put them in columns and in rows? MENDELEEV! Who was ready who was able to make a periodic table? Who was that chemist? MENDELEEV!

Mendeleev So they called him the father of the periodic table, And his work gave rise to another kind of label, It’s the name for element number 101 Mendelevium. In honor of this man they call it Mendelevium.

Mendeleev Who told the elements where to go? MENDELEEV! Who put them in columns and in rows? MENDELEEV! Who was ready who was able to make a periodic table? Who was that chemist? MENDELEEV! Mendeleev  The father of modern periodic table