n° = 20 e- = 18 2- D) Ca E) S ____________________________________________________________________________ 5) What mass in grams does 2.87 moles of sodium atoms have? 25 A) 1.39 x 10 B) 66.0 C) 8.01 D) 1.39 x 10 24 E) 1.73 x 10 24 ____________________________________________________________________________ 6) How many potassium atoms are contained in 15 g of potassium? 23 26 24 A) 2.3 × 10 B) 3.5 × 10 C) 9.0 × 10 D) 1.6 × 10 24 25 E) 3.3 × 10 ____________________________________________________________________________
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modern concept of the atom. I am going to give a brief history of the atomic model including Thomson’s atom‚ Rutherford’s atom‚ Bohr’s atom‚ and Schrödinger’s atom. I am going to include a diagram for each of these models. In 1897 physicist‚ J.J. Thomson‚ shortly after discovering electrons‚ proposed his Plum-Pudding model of the atom. He based this model on the two facts that he knew at the time: 1. atoms contain small negatively charged particles called electrons and 2. atoms behave as if they
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Chemistry revision Atoms elements and compounds Atom-the smallest part of an element that can still be recognized as an element Element-a substance made up of only one type of atom. An element cannot be broken down chemically into any simpler substance Nucleus-middle of the atom‚ which contains protons and neutrons Electron-tiny particle‚ which surrounds the nucleus with a negative charge Compound-when two elements react and combine together which contain more than one element. There
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Notes on the history of the atom In 1897 the British physicist Joseph John (J. J.) Thomson (1856–1940) discovered the electron in a series of experiments designed to study the nature of electric discharge in a high-vacuum cathode-ray tube‚ an area being investigated by numerous scientists at the time. Thomson interpreted the deflection of the rays by electrically charged plates and magnets as evidence of &quotbodies much smaller than atoms&quot that he calculated as having a very large value
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BHARATHI MATRIC HR. SEC. SCHOOL KALLAKURICHI STD: X SUB: SCIENCE PRE QUARTALY TIME: 3.00 MARK: 100 PART-A I. Choose the correct answer 15x1=15 1. Pick out the wrong statement (a) In a dicot seed there is a short longitudinal whitish ridge is called the Raphael (b) There is a minute opening in dicot seed is known as micropyle . (c) The rudimentary stem portion known as radical. (d) The rudimentary root portion is called radical. 2. The roots of coconut tree are seen
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computers and television‚ and a host of essential services that we take for granted. However‚ electricity has much more important aspects because it is a fundamental feature of all matter. Electricity is the force that holds together the molecules and atoms of all
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Chapter 2 The History of the Atom It took many scientists and philosophers hundreds even thousands of years to come up with an accurate atomic theory. For nearly 2‚000 years science was unable to come up with experiments that were able to test and put forth the theories made up by Democritus which was a fifth century B.C. Greek philosopher. In 1803‚ John Dalton‚ who viewed the atom as a small solid sphere‚ and is credited for the developing of the first coherent atomic theory was now in the picture
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BOHR’S MODEL OF ATOM MADE BY:-GROUP-1{CHEMISTRY} About The Scientist……. HE was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory‚ for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and a promoter of scientific research. He was born in Copenhagen on 7 October 1885. He wrote many books like the theory of spectra and atomic constitution‚ atomic theory and the description of nature. NEILS BOHR
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Science Chpt 11 and 12 Study Guide Name _________________ Chpt 11 1. Democritus named the atom. The word atom means __________________________ 2. Define atom and determine if you can or cannot divide it into simpler substances. – 3. List the 3 subatomic particles of the atom are and their charges a. b. c. Be able to identify those particles on a diagram!!! 4. Be able to label a diagram of a atom using information from the Periodic Table 6 _________________________ ______________________
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Over time many theories have been developed into the structure of the atom and what the world around us is composed of. Many scientists and philosophers have dedicated their life works into trying to understand how atoms work and what they are made up of‚ although not all theories have been accepted they have all come together to form what we know today. It all started from a Greek scientist called Democritus‚ who developed the idea that everything is made up of smaller things‚ which he named atomos
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