Atomic Models PDF

theory C ATOMIC MODELS 1 Solid Sphere Model 2 Plum Pudding Model 3 Nuclear Model 4 Planetary Model 5 Quantum Model  ATOMIC THEORY TIMELINE 1803 1897 1911 191...

theory C ATOMIC MODELS 1 Solid Sphere Model 2 Plum Pudding Model 3 Nuclear Model 4 Planetary Model 5 Quantum Model  ATOMIC THEORY TIMELINE 1803 1897 1911 1913 1920s Solid Plum Nuclear Planetary Quantum Sphere John Pudding Joseph John Ernest Rutherford Niels Erwin Schrödinger Dalton Thomson Bohr Atoms are dense and solid, Atoms are described as Atom consists of a small, Electrons move in Electrons do not have with no internal structure or uniform, positively charged dense, positively charged quantized, discrete energy definite orbits, but are subatomic particles spheres with electrons nucleus at the center, with levels around the nucleus described by wave considered. embedded within them, electrons orbiting around it, and emit or absorb energy functions that represent similar to raisins in a similar to planets orbiting when transitioning between probability distributions of pudding. around the sun. levels. their locations. Basic Postulates of Dalton's Atomic Theory: Matter is made up of extremely small and 1 indestructible particles called atoms. 2 All atoms of a given element are alike. Atoms enter into combination with other atoms 3 to form compounds but remain unchanged during ordinary chemical reactions. 4 Atoms can combine in simple numerical ratios such as 1:1, 1:2, 2:3, and so on.  Basic Postulates of Dalton's Atomic Theory: Atoms 1 can combine in simple numerical ratios such as 1:1, 1:2, 2:3, and so on. 3 4 5 Plum Pudding Atomic Model: 1 Positively Charged Sphere 5 Loosely embedded electrons Nuclear Atomic Model: ❖ Ernest Rutherford (1871-1937), a British physicist, completely unraveled Becquerel rays. ❖ discovered 1 (with his coworkers) that the rays are of three types ---- alpha (α), beta (β), and gamma. RUTHERFORD’S ALPHA-SCATTERING EXPERIMENT 3 4 5  RUTHERFORD’S ALPHA-SCATTERING Nuclear Atomic Model: EXPERIMENT 1 3 4 5  RUTHERFORD’S ALPHA-SCATTERING Nuclear Atomic Model: EXPERIMENT 1 3 4 5 ❖ James Chadwick (1891-1974), a British physicist, discovered neutron. Bohr's Planetary Model Bohr's model proposed that electrons orbit the nucleus in specific energy levels. It revolutionized the understanding of atomic structure. ❖ Niels Bohr (1885-1962), a Danish physicist, proposed the first workable theory of atomic structure. Here are the following postulates: 1. A hydrogen atom consists of a nucleus containing a proton and an electron. The electron revolves around the nucleus in a circular orbit. There is a force of attraction between the nucleus and the electron. This force balances the centrifugal force on the electron. 2. Only certain circular orbits are permitted. 3. The energy of electron in a given orbit is fixed. As long as the electron stays in that orbit, it neither absorbs nor radiates energy. The non-radiating state is called the stationary state. 4. The electron may move from one stationary state to another. To do so, it must absorb or emit a quantity of energy exactly equal to the difference in energy between the two states. Electrons normally exist in the lowest energy state called the ground state. When an electron goes to a higher energy state, it is said to be in an excited state. 4. The electron may move from one stationary state to another. To do so, it must absorb or emit a quantity of energy exactly equal to the difference in energy between the two states. Why does sodium chloride give off a yellow flame when heated?  Electrons normally exist in the lowest energy state called the ground state. When an electron goes to a higher energy state, it is said to be in an excited state. Example: when sodium becomes excited, it emits a characteristic spectrum in the yellow region. This accounts for the yellow color of the sodium vapor lamps.  On a piece of paper, write your idea or ideas on each of the following concepts: ∙ John Dalton’s Basic Postulates of Atomic Theory ∙ Sir Joseph John Thomson’s Atomic Model ∙ ∙ Rutherford’s Alpha-Scattering Experiment ∙ Niels Bohr’s Postulates of Atomic Theory Group Activity: FORM four groups. Each group will do a role play about the concepts discussed by the scientists. Rubric: Knowledge of concept: 50% Presentation/Delivery: 50% Write true or false. 1. Based on Rutherford’s alpha-scattering experiment, most of the alpha particles passed through with large angles of deflection. 2. Sir Joseph John Thomson suggested that atom was composed of a positively charged sphere with loosely embedded electrons on the surface. 3. The electron revolves around the nucleus in a circular orbit. There is a force of attraction between the nucleus and the electron according to Niels Bohr.  Using the Periodic Table of the Elements, write the correct chemical names of these two elements, mass numbers, atomic numbers, and the number of their particles. An atom is composed of protons, electrons, and neutrons. The nucleus is the central core of an atom. Protons and neutrons have almost the same mass and are about 2000 more massive than an electron. Protons and neutrons are collectively called nucleons.  nucleus has nucleons. C  Major Constituents of an Atom Particle Electronic (Symbol) Charge (C) charge Mass (kg) Location -19 -31 Electron (e) -1.60 x 10 -1 9.109 x 10 Outside nucleus -19 -27 Proton (p) +1.60 x 10 +1 1.673 x 10 Nucleus -27 Neutron(n) 0 0 1.675 x 10 Nucleus The nucleus contributes more than 99.97% of the mass. Electron orbits determine the size or volume of atoms.  The particles in an atom are designated by certain numbers. ATOMIC NUMBER (symbolized by letter Z) – the number of protons in the nucleus of each atom of that element. MASS NUMBER (A) – the number of protons plus neutrons X in the nucleus; the total number of ______. NEUTRON NUMBER (N) – the number of neutron in the nucleus. NEUTRON NUMBER (N) = mass number – atomic number X An element is a substance in which all the atoms have the same number of protons (same atomic number).  An element is a pure substance made up of only one type of atom. There are 118 known elements, each with its own unique properties. Atoms that have the same number of protons but differ in their numbers of neutrons are known as the isotopes of that element. CARBON-12 CARBON-13 CARBON-14  Isotope Protons Neutrons Mass number Protium 1 1 (99.984%) deuterium 1 2 (0.016%) tritium 1 3 (artificially produced radioactive isotope) Do isotopes of an element have the same physical and chemical properties?  Isotopes of an element have the same chemical properties because they have the same number of electrons, which determine chemical activity and reactions.  Isotopes of an element have different physical properties because they have different masses.  The Atomic Mass Generally, each element occurs as a combination of its isotopes. The weighted average mass of an atom of the element in a naturally occurring sample is called the atomic mass. The atomic mass is expressed in atomic mass unit (u). 1 u = 1.66054 x 10-27 kg. Determine the number of protons, electrons, and neutrons in iodine-131. Element Atomic Mass Protons Electrons Neutrons Number Number Na 11 23 11 11 12 Ac 227 89 Ni 59 28 U 92 146 H 1 0  sodium - natrium silver - argentum gold - aurum iron - ferrum ELEMENTS & tin - stannum lead - plumbum THEIR LATIN copper - cuprum NAMES mercury - hydrargyrum potassium - kalium Determine the number of protons, electrons, and neutrons in iodine-131.  Names and Symbols of the Elements Element Symbol Atomic Number Classic Name Aluminum Al 13 Antimony Sb 51 Stibium Arsenic As 33 Barium Ba 56 Beryllium Be 4 Boron B 5 Calcium Ca 20 Carbon C 6 Chlorine Cl 17 Chromium Cr 24 Copper Cu 29 cuprum  Names and Symbols of the Elements Element Symbol Atomic Number Classic Name Fluorine F 9 Gallium Ga 31 Gold Au 79 aurum Helium He 2 Hydrogen H 1 Iodine I 53 Iron Fe 26 ferrum Lead Pb 82 plumbum Magnesium Mg 12 Manganese Mn 25 Mercury Hg 80 hydrargyrum  Names and Symbols of the Elements Element Symbol Atomic Number Classic Name Molybdenum Mo 42 Neon Ne 10 Nitrogen N 7 Oxygen O 8 Platinum Pt 78 Plutonium Pu 94 Potassium K 19 kalium Radium Ra 88 Silicon Si 14 Silver Ag 47 argentum sodium Na 11 natrium Names and Symbols of the Elements Element Symbol Atomic Number Classic Name Strontium Sr 38 Sulfur S 16 Tin Sn 50 stannum Titanium Ti 22 Tungsten W 74 wolfram Uranium U 92 zinc Zn 30 Schrodinger's Quantum Mechanical Model Schrodinger's model uses quantum mechanics to describe the behavior of electrons in atoms. It predicts the probability of finding electrons in specific regions around the nucleus.