Development of Atomic Models Grade 9 Science PDF
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This document provides a summary of the development of atomic models, starting with the historical perspectives and leading up to modern atomic models like the quantum model. It also includes guide questions to further explore the topic.
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Grade 9 Science Developmen t of Atomic Models Watch and make a timeline out of the video. https://www.youtube.com/watch?v=Qesxa71vfkM Guide Questions: 1. How did the development of atoms start? 2. How did the scientists come up with the different models? 3. What a...
Grade 9 Science Developmen t of Atomic Models Watch and make a timeline out of the video. https://www.youtube.com/watch?v=Qesxa71vfkM Guide Questions: 1. How did the development of atoms start? 2. How did the scientists come up with the different models? 3. What are the different types of atomic model? Solid Sphere Model -1803 Dalton grew upon the Ancient Greek idea of atoms (the word atom comes from the Greek ‘atomos’ meaning indivisible. His theory stated that atoms are indivisible, those of a given element are identical, and compounds are combinations of to Dalton: All mater is made up of atoms. Atoms are indivisible and indestructible. All atoms of a given element are identical in mass and properties. Compounds are formed by a combination of two or more different kinds of atoms. A chemical reaction is a rearrangement of atoms; and Atoms can be neither created nor destroyed. Plum Pudding Model -1903 Thomson discovered electrons (which he called ‘corpuscles’) in atoms in 1897, for which he won a Nobel Prize. He subsequently produces the ‘plum pudding’ model of the atom. It shows the atoms as composed of electrons scattered throughout a spherical cloud of to THOMSOM: An atom consists of a sphere of positive charge with negatively charged electron embedded in it. The positive and negative charges in an atom are equal in magnitude, due to which an atom is electrically neutral. It has no over all negative or positive charge. Rutherford fired positively charged Nuclear Model alpha particles at a thin sheet of -1911 gold foil. Most passed through with little deflection, but some deflected at large angles. This was mostly empty space, with the positive charge concentrated in the center: the nucleus. to RUTHERFORD: An atom must have almost all of its mass concentrated at its center, in a nucleus, with the vast majority of the atom consisting chiefly of empty space. Planetary Model -1913 Bohr modified Rutherford’s model of the atom by stating that electrons moved around the nucleus in orbits of fixed sizes and energies. Electro energy in this model was quantized; electrons could not occupy values of energy between the fixed energy levels. Quantum Model -1926 Schrodinger stated that electrons do not move in set paths around the nucleus, but in waves. It is impossible to know the exact location of the electrons; instead we have ‘clouds of probability’ called orbitals. In which we are more likely to find an electron. 1. Whose model suggested that negative particles were mixed in with positively charged material - like seeds in a watermelon? 2. Who discovered that the atom had QUIZ TIME! a small, dense, positively charged center? What are the different components of blood? Answer the following: 3. Who named the positive center of the atom the "nucleus?" 4. Which scientist discovered that the atom has parts - which means it can be divided? 5. Which scientist believed that elements differed from one another ASSIGNMENT: Research on how atoms combine with other atoms by transferring or by sharing electrons.
