Antoine Lavoisier,1778 a French scientist,renamed Priestley's gas oxygen,from the Greek words that loosely translate as "acid maker". Lavoisier knew from other scientists before him that acids react with some metals to release another strange and highly flammable gas called phlogiston.he renamed phlogiston hydrogen,from the Greek words for "water maker". Lavoisier also burned other substances such as phosphorus and sulfur in air, and showed that they combined with air to make new materials.These new materials weighed more than the original substances,and Lavoisier showed that the weight gained by the new materials was lost from the air in which the substances were burned.From these observations,Lavoisier established the Law of Conservation of Mass,which says lost or gained during a chemical reaction. An eighteenth-century chemistry bench
Antoine Lavoisier, 1778 • a French scientist, renamed Priestley’s gas oxygen, from the Greek words that loosely translate as "acid maker". • Lavoisier knew from other scientists before him that acids react with some metals to release another strange and highly flammable gas called phlogiston. he renamed phlogiston hydrogen, from the Greek words for "water maker". • Lavoisier also burned other substances such as phosphorus and sulfur in air, and showed that they combined with air to make new materials. These new materials weighed more than the original substances, and Lavoisier showed that the weight gained by the new materials was lost from the air in which the substances were burned. From these observations, Lavoisier established the Law of Conservation of Mass, which says that mass is not lost or gained during a chemical reaction. An eighteenth-century chemistry bench
John Dalton,1803 an exceptional British teacher and scientist,put together the pieces and developed the first modern atomic theory.Dalton's Playhouse ● a regular habit to track and record the weather in his home town of Manchester,England. classic 1808 paper A New System of Chemical Philosophy 厘L面料Y: ⊙606g由6⊙ ELEMENTS 06866666 ⊙ 与yd5cn 13 Stntian 6666 ① Bauvies ⊙ Iion O ⑦ Zic Copper 0 品品品A ⊕ ⊙ Lead ③ Silver 88 @ Gold Soda 28 p Platina too Potash样 Mercury1 Dalton's Elements
John Dalton, 1803 • an exceptional British teacher and scientist, put together the pieces and developed the first modern atomic theory. Dalton's Playhouse • a regular habit to track and record the weather in his home town of Manchester, England. • classic 1808 paper A New System of Chemical Philosophy Dalton’s Elements
All matter is composed of indivisible particles called atoms.tiny billiard-ball-like particles in various states of motion. All atoms of a given element are identical;atoms of different elements have different properties.atomic weight;however,when isotopes of elements were discovered in the late 1800s this concept changed. Chemical reactions involve the combination of atoms,not the destruction of atoms.100 years before scientists began to explain the concept of chemical bonding. When elements react to form compounds,they react in defined,whole- number ratios
• All matter is composed of indivisible particles called atoms. tiny billiard-ball-like particles in various states of motion. • All atoms of a given element are identical; atoms of different elements have different properties. atomic weight; however, when isotopes of elements were discovered in the late 1800s this concept changed. • Chemical reactions involve the combination of atoms, not the destruction of atoms. 100 years before scientists began to explain the concept of chemical bonding. • When elements react to form compounds, they react in defined, wholenumber ratios
Some related concepts Elements:As early as 1660,Robert Boyle recognized that the Greek definition of element (earth,fire,air,and water)was not correct.Boyle proposed a new definition of an element as a fundamental substance,and we now define elements as fundamental substances that cannot be broken down further by chemical means. Atoms:A single unit of an element is called an atom.The atom is the most basic unit of the matter that makes up everything in the world around us. Each atom retains all of the chemical and physical properties of its parent element. Proust's Law of Definite Proportions: 2 parts hydrogen 1 part oxygen 1 part gaseous water 4 parts hydrogen 2 parts oxygen 2 parts gaseous water 2 parts hydrogen 2 parts oxygen 1 part gaseous water 1 part oxygen
Some related concepts • Elements: As early as 1660, Robert Boyle recognized that the Greek definition of element (earth, fire, air, and water) was not correct. Boyle proposed a new definition of an element as a fundamental substance, and we now define elements as fundamental substances that cannot be broken down further by chemical means. • Atoms: A single unit of an element is called an atom. The atom is the most basic unit of the matter that makes up everything in the world around us. Each atom retains all of the chemical and physical properties of its parent element. • Proust’s Law of Definite Proportions:
1897,J.J.Thomson if an electric current was passed through a vacuum tube,a stream of glowing material could be seen the mysterious glowing stream would bend toward a positively charged electric plate Thomson theorized that the stream was in fact made up of small particles,pieces of atoms that carried a negative charge.These particles were later named electrons. Thomson imagined that atoms looked like pieces of raisin bread,a structure in which clumps of small,negatively charged electrons(the "raisins")were scattered inside a smear of positive charges
1897, J. J. Thomson • if an electric current was passed through a vacuum tube, a stream of glowing material could be seen • the mysterious glowing stream would bend toward a positively charged electric plate • Thomson theorized that the stream was in fact made up of small particles, pieces of atoms that carried a negative charge. These particles were later named electrons. • Thomson imagined that atoms looked like pieces of raisin bread, a structure in which clumps of small, negatively charged electrons (the "raisins") were scattered inside a smear of positive charges