How Did Henry Mozelsey Define The Atomic Number Of Element

he atom or Atomos, which means uncuttable or indivisible, took many years to get to our understanding now. Back then they didn’t have the technology that we have now like microscopes, to figure everything out. Some important people who helped were Greek philosopher Leucippus and his student Democritus. They were the first came up with the idea that matter is made up of of tiny particles. They thought that if you cut something in half a lot times, that you will eventually reach a particle that can't be cut anymore. The next big discovery in the atom didn’t come until hundreds of years later by James Dalton, who stated that atoms of different elements have different masses. Throughout Dalton's life as a chemist he had many theories of the

-Henry Gwyn Jeffreys Moseley- Worked with Ernest Rutherford, experimented with 38 metals, he found that the positive charge of each element’s nucleus increased by one from element to element as they were arranged in Mendeleev’s periodic table, lead to modern definition of atomic number (# of protons in atom’s nucleus) and the recognition the

Around 2,500 years ago, Democritus and his partner Leucippus were the first ones to develop the atomic theory in written history. Their theory proposed that every kind of matter was made up of tiny particles, which were named atomos, which means that it is indivisible. This meant that Democritus and Leucippus thought there were little particles of everything, but, the next breakthrough in atomic theory wasn’t made until the early 1800s with a french chemist by the name of Antoine Lavoisier, he was the one who came up with the idea of the law of the conservation of mass, which states that matter stays the same even when it changes shape or form. Then, James Dalton said that all matter was made up of atoms, which were indivisible, and unbreakable.

The History of the Periodic Table of elements is vast, and filled with interesting facts that not many average people would know about, these four scientists have had all contributed to the table in some way, and lead it to its current state, here is what they have

Stanislao Cannizzaro was born on July 13, 1826. When he was younger, he showed great skills in mathematics. He later became an assistant to Rafaelle Piria. Cannizzaro saw his dedication to his work that Piria influenced him to transform his study to chemistry. Cannizzaro later determined the different atomic weights. Dmitri Ivanovich Mendeleev always had a love for history, math, and physics. He attended the University of St. Petersburg where he formed the ideas of chemical compounds. Mendeleev found out that you could simplify the periodic table by separating them into different groups. He arranged them by the atomic weights and then later realized they had similar chemical properties. He had also given predictions of future elements and their properties.

- The discovery of neutrons solved the mystery why atomic mass and atomic number are different, since neutrons added mass to the atom but don’t add any

Ernest Rutherford, 31 year old New Zealander, partners with Frederick Soddy to try and solve the mystery of uranium. They find that uranium spits out chunks of itself, and these chunks are radiation. The uranium then transforms into a completely different element. When the uranium spit out chunks of itself, it was losing protons so it no longer has 92. This is called transmutation.

Other scientists like J.J. Thomson helped develop the overall knowledge of chemistry, especially with his discovery about the first subatomic particle, the electron, in 1897. However, despite Thomson’s important breakthrough, Bohr’s discovery in the early 1900’s developed a strong basis and knowledge about the entire atom’s appearance and what it contained which made a significant impact on chemistry. Bohr’s innovation was published as a model that established the theory of electrons moving in orbits around the nucleus of the atom. He also introduced the idea of the chemical properties of the element being mostly governed by the number of electrons located in the outermost orbits. It can be argued that discovering the electron itself before Bohr’s research is more important to his own discovery, but without his new discovery, the theory of electrons wouldn’t have been determined later along with the base principles of electrons and how they interact. Furthermore, any knowledge about the electron cloud would be compact without pivotal knowledge of what an atom looks

In the 18th, century many elements were starting to be discovered so scientists faced the problem of trying to arrange them. At this time the actual masses of the elements could not be measured so instead they compared them with the mass of hydrogen, or the relative atomic mass.

Even before he knew anything about the atom or its behavior, a Russian scientist by the name of Dmitry Mandeleev was able to organize known elements of the time by their common properties. He noticed that the properties would appear periodically and began organizing the elements in columns that shared those similar properties. Thus, the periodic table was born.2 In this lab session, the chemical and periodic properties of several substances were observed to determine trends and differences among them. These properties include, but are not limited to, acidity and basicity, the production of gases,

Since the ancient times, people like the Greeks were acknowledged of the existence of elements, but only knew of common ones like gold, tin, and copper. It wasn't until the middle of the nineteenth century when about 50 elements were discovered and scientists began to wonder if the elements vary from each other or if a pattern is represented in the arrangement of the elements. A number of scientists tried different kinds of patterns. For example, the German scientist Johann Wolfgang Döbereiner tried grouping the three halogens elements (chlorine, bromine, and iodine) in a consecutive order of atomic weights. The idea of putting the elements together finally took shape when the two scientists, Dmitry Mendeleev and Julius Lothar Meyer

He continued his way and put forward the elements in order of increasing atomic mass and wherever he found a interval, simply assumed that this elements had not discovered yet. His way helped him to work out the atomic mass of undiscovered elements and predict their properties which the later on the new elements discovered it could go to the right place in his table. He put the elements in order of relative atomic mass and this gave a problem. For example: Iodine with lower atomic mass was after Tellurium in table and that breaking his rules.

Since the earliest of times, scientists and philosophers have known that the universe is more than just what it appears to be, but instead there is a deeper, more complex makeup beneath the surface. The ancient Greeks called it “the four elements”2, though some, like Democritus, believed that everything was made of tiny indivisible particles called atoms.3 Later, however, with advancements in technology, scientists such as John Dalton, JJ Thomson, Ernest Rutherford, and James Chadwick were able to prove the existence of an indivisible particle with a dense, positively charged nucleus consisting of protons and neutrons with electrons orbiting the nucleus.1 With this knowledge, others were able to dig deeper, and discover so much more about atomic theory, such as Brown’s equation for the motion of an electron,6 Dirac’s discovery of the positron,11 Fermi’s research in nuclear fission to create the atomic bomb,13 and Gell-Mann’s discovery of the quark.14 Each discovery made by these men has shaped the world in some way or another, and even now more discoveries are being made, but only because of the foundation laid out by those who set atomic

Scientists all around the world have attempted to group, sort and organise elements together for hundreds of years, with initial classification systems dating decades before the dawn of an actual table in the nineteenth century. An example of early work prior to the 1800s is Antoine Lavoisier and partners Antoine Fourcroy, Louis-Bernard Guyton de Morveau and Claude-Louis Berthollet’s list of elements. While this one dimensional system documented all of the 33 elements known at the time (and still shares the same idea of organising the elements), sorting them based on a variety of physical factors proved to be much more complex than imagined (Scerri, 2011).

Elements are the basic building blocks of matter due to the fact that they are chemically the simplest substances. Whether we can find them in the air or in our gold/silver necklaces, elements are everywhere! One essential element is hydrogen, the first element on the period table (located under Group 1 as an alkaline metal) is composed of a single proton and electron; therefore having an atomic number and atomic mass of 1 and electron configuration of 1s1. In fact, hydrogen is the lightest, simplest and most commonly found chemical element in the universe (it makes up about 90% of the universe by weight). Interestingly enough, the heavier elements on the periodic table were either made from hydrogen or other elements that were made