Atomic mass unit

Chemistry is a branch of science that studies matter, its composition and properties. Matter is anything that has mass and takes up space; the universe and anything in it is made up of matter. There are smaller units of matter called atoms. Atoms are the building blocks of matter. The concept of the atom wasn’t introduced by scientists until the 1800s. As scientists collected experimental evidence about atoms, they learned that atoms are made up of even smaller particles- protons, neutrons and electrons

In chemistry and physics, atomic theory is a scientific theory of the nature of matter, which states that matter is composed of discrete units called atoms. It began as a philosophical concept in ancient Greece and entered the scientific mainstream in the early 19th century when discoveries in the field of chemistry showed that matter did indeed behave as if it were made up of atoms. The word atom comes from the Ancient Greek adjective atomos, meaning "uncuttable". 19th century chemists began using

Dimitri Mendeleev a Russian chemist began the periodic table in 1869. He began by rearranging the elements by their atomic mass. He left blank spaces since there was a lot more discovery to be made later down the road. A physicist named Atonie Bequerel was the first to discover radioactivity. Ernest Rutherford was the first to discover alpha, beta, and gamma rays. Noble gases, electrons, protons, lanthanides and actinides were also discovered by several other scientists. The periodic table began

Introduction This experiment had two objectives: 1) to determine the atomic mass of pure aluminum, and 2) to determine the masses of aluminum and zinc in an unknown aluminum alloy. To fulfill both of these objectives, both pure aluminum and the unknown alloy were reacted with HCl in order to produce a chemical and H2 gas. The reaction of aluminum and zinc with HCl are found below: 2Al(s) + 6HCl(aq) ⟶ 2AlCl3(aq) + 3H2(g) 2Zn(s) + 6HCl(aq) ⟶ 2ZnCl3(aq) + 3H2(g) Both metal samples would dissolve into

Early atomic model experiments Thomson’s discovery of the electron in 1897 and the atomic model, with his findings of the atom containing electrons, each with an individual unit of negative charge. Thomson also found that electrons were very light when compared to the mass of the atoms in which they came from. This is because atoms were known to be electrically neutral, the remainder of the atom had to be positively charged and form most of the weight in the atom. Thomson used his plum pudding model

The Element Oxygen has a chemical symbol O and atomic number 8. Oxygen was produced by numerous chemists prior to discovery in 1774, but each chemist failed to record it as an element. The main people are British clergyman Joseph Priestley, Swedish pharmacist Carl Wilhelm Scheele and French chemist Antoine Laurent Lavoisier all independently discovered oxygen. But Priestley usually gets the credit for the discovery. The name oxygen was first used by Lavoisier in 1777. Oxygen plays an essential

out of the United States’ fear that Germany may have created weapons of mass destruction (Bateman 2004, 109; Historic Wendover Airfield Foundation 16). It was imperative for the U.S. to harness atomic power before Hitler and the axis powers could use it against the allied forces (Posey 2011). It is important to note that while Colonel Tibbets understood his assignment of delivering the atomic bomb to Japan, members of his unit only knew their specific job at Wendover. Secrecy was of utmost importance

The rate of effusion of a gaseous substance is inversely proportional to the square root of its molar mass. where: Rate1 is the rate of effusion of the first gas (volume or number of moles per unit time). Rate2 is the rate of effusion for the second gas. M1 is the molar mass of gas 1 M2 is the molar mass of gas 2. Graham's law states that the rate of diffusion or of effusion of a gas is inversely proportional to the square root of its molecular weight. Thus, if the molecular weight of one gas is

History of the Atomic Model Paper Philip Wang Over the course of the last 5000 years, mankind’s knowledge has been constantly advancing. Chemistry, a branch of science, has experienced a tremendous leap and expansions since ancient Greek civilization. One of the major breakthroughs in the advancement in Chemistry was the creation of the Atomic theory, which laid a foundation for the modern-day Chemistry and future of science. The Atomic theory introduced the idea of atoms, which are defined as

genocide would be the US dropping the atomic bomb on Hiroshima and Nagasaki, Japan. The holocaust which killed over 6 million jews. And the events that happened in Rwanda where the hutus killed over 800 000 tutsi in a span of 100 days. These are only a few of the many tragic events of crimes against humanity that have occurred over the thousands of years that humans have roamed the earth. The dropping of the atomic bomb called little boy was the first atomic bomb ever to be dropped. The dropping