Chemistry Atomic Structure Presentation - PDF

EARLY ATOMIC THEORIES & PROPERTIES OF AN ATOM Ancient Greece Greek philosopher He theorized that all material bodies are made up of indivisibly small “a tomos.” Democritus held that "All matter could be subdivi...

EARLY ATOMIC THEORIES & PROPERTIES OF AN ATOM Ancient Greece Greek philosopher He theorized that all material bodies are made up of indivisibly small “a tomos.” Democritus held that "All matter could be subdivided only until some finite particle was reached." DEMOCRITUS JOHN DALTON British chemist and physicist Proposed the Solid Sphere Model in the early 19th century His fascination with gases led him to conclude that all matter, whether liquid, solid, or gaseous, is composed of small individual molecules. ATOMIC THEORY SOLID SPHERE MODEL Atoms are dense and solid, with no internal structure or subatomic particles considered.  English physicist known for his work on the nature of electrons Proposed the Plum Pudding Model in the late 19th century A series of experiments with cathode rays he carried out J.J. THOMSON near the end of the 19th century led to his discovery of the electron Image of J.J. Thomson (seen here in his lab with one of his many hand-made cathode ray tubes) ATOMIC THEORY PLUM PUDDING MODEL Atoms are described as uniform, positively charged spheres with electrons embedded within them, similar to raisins in a pudding. ERNEST RUTHERFORD New Zealand-born physicist known for his contributions to nuclear physics Introduced the Nuclear Model in the early 20th century While studying the effects of X-rays on gases he decided to look more closely on atoms. ATOMIC THEORY NUCLEAR MODEL Atom consists of a small, dense, positively charged nucleus at the center, with electrons orbiting around it, similar to planets orbiting around the sun.  WHAT IS AN ATOM? Atoms are the basic particles of the chemical elements. An atom consists of a nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons.  ATOMS & ELEMENTS Atoms are the microscopic and indivisible building blocks that make up the elements of the universe. Elements are the purest form of matter; they cannot be broken down into simpler substances.  SUBATOMIC PARTICLE All atoms are made of subatomic particles, listed below: Nucleus = Protons have a mass of 1 atomic mass unit and a charge of +1. | They are fixed in place in the nucleus of the atom. = Neutrons have a mass of 1 amu and no charge. They are fixed in place in the nucleus of the atom. = Electrons have a mass of 0 amu and a charge of -1. Due to their size and location on the outside of the atom, they are highly O - Electron mobile and can be lost or gained by an atom. O + Proton O N Neutron model of the atom AIdalla, Charles Angel B. Bs Psychology- 3A (batch 1) Neil Bohr`s Niels Henrik David Bohr: A Pioneer in Physics and Philosophy Niels Henrik David Bohr was a Danish physicist and philosopher who made significant contributions to atomic structure and quantum theory. He developed the Bohr model of the atom, proposing that electrons have discrete energy levels and can jump between energy levels. Bohr's concept of complementarity, which allows for separate analysis of items in terms of contradictory properties, dominated his scientific and philosophical thinking. Bohr founded the Niels Bohr Institute, now known as the Niels Bohr Institute, in 1920. He predicted the properties of a new zirconium-like element, named hafnium, and later the synthetic element bohrium. Bohr helped refugees from Nazism during the 1930s and later joined the British Tube Alloys nuclear weapons project and the Manhattan Project. After the war, Bohr called for international cooperation on nuclear energy and became the first chairman of the Nordic Institute for Theoretical Physics in 1957. SOLAR SYSTEM  PROTON ELECTRON ORBITAL Atom A SUBATOMIC A REGION OF SPACE WITHIN AN ATOM WHERE PARTICLE WITH A AN ELECTRON IN A GIVEN POSITIVE ELECTRIC SUBSHELL CAN BE FOUND CHARGE. ELECTRON AN ELEMENTARY PARTICLE THAT HAS A NEGATIVE CHARGE OF ELECTRICITY AND TRAVELS AROUND THE NUCLEUS OF AN ATOM. ATOMIC DIAGRAM  THE QUANTOM MECHANICS MODEL describes the probability of finding electrons within given orbitals, or three-dimensional regions of space, within an atom There are three physicists that led us to the development of a better model of the atom Louie de Broglie Erwin Schrodinger Karl Heisenberg  De Broglei Model introduced the idea that particles, such as electrons, could be described not only as particles but also as waves. This was substantiated by the way streams of electrons were reflected against crystals and spread through thin metal foils  Schrodinger Model is a wave and tries to describe the regions in space, or orbitals, where electrons are most likely to be found. Instead of trying to tell us where the electron is at any time, the Schrödinger model describes the probability that an electron can be found in a given region of space at a given time. This model no longer tells us where the electron is; it only tells us where it might be.  Heisenberg Model uncertainty Principle - you can`t locate the exact position of an electron at any given time ( too small, too fast) Atomic orbitals The volume of region of space around the nucleus where electron is most likely to be found the Principle energy levels are broken down into sublevels. these sublevels define the orbitals shape ( S,P,D,F) comes from mathematical solution to the Schrodinger equation. it views an electron as a cloud of negative charge having a certain geometric the figure shows that the darker an area the greater is the probability of finding the electron in that area