The Structure of an Atom
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Atoms are the basic building blocks of all matter and are made up of a nucleus containing protons and neutrons surrounded by electrons. John Dalton's atomic theory established that atoms are indivisible and that different elements are composed of different types of atoms. Rutherford discovered that the nucleus contains a concentrated positive charge and most of an atom's volume is empty space. Niels Bohr's model represented electrons orbiting the nucleus in fixed energy levels like planets around the sun, explaining atoms' distinct properties and how they form bonds.
The Structure of an Atom
- 2. PREPARED BY LEKSHMI.S.G PHYSICAL SCIENCE REG NO: 13357003 BNVCTE,THIRUVALLAM
- 4. All matter is made up of atoms. Atoms of an element are identical. Each element has different atoms. Atoms can engage in a chemical reactions. Atoms can neither be created nor be destroyed. Atoms are indivisible. Atomic Theory John Dalton (1776-1884)
- 5. atom has a positively charged central part (nucleus) Electrons are distributed around nucleus Mass of an atom is concentrated at nucleus. Compared with total volume of an atom, the volume of nucleus is meager Rutherford’s Atomic Model Ernest Rutherford (1871-1937)
- 6. Solar system Rutherford‘s atom model Planetary model of atom
- 7. Bohr's Model of the Atom Niels Bohr 1913
- 8. Bohr's Model of the Atom electrons orbit the nucleus like planets orbit the sun
- 9. Bohr's Model of the Atom electrons fills the orbits closest to the nucleus e.g. fluorine: #P = 9 #e- = 9 #N = 10 9P 10N
- 10. each orbit can hold a specific maximum number of electrons Shell maximum no: of electrons 1 - K 2 - L 3 - M 4 - N Bohr's Model of the Atom 2 8 18 32
- 12. What is the structure of an atom? • Nucleus - center of the atom Home of Protons and Neutrons Has a positive charge • Proton Has a relative mass of 1 Has a positive (+) charge Determines the atomic number Found inside the nucleus
- 13. What is the structure of an atom? • Neutron Has no (0) charge Has a relative mass of 1 Found inside the nucleus
- 14. What is the structure of an atom? • Electron Has a negative (-) charge Found outside the nucleus • Rutherford atom model - electrons are around the nucleus • Bohr model – electrons are in specific energy levels called shells
- 15. How are p, n, e related? • No: protons = No: electrons • No: protons = atomic number • No: protons + No:neutrons = mass number • No: neutrons=mass no: - atomic no:
- 16. ATOMIC STRUCTUREATOMIC STRUCTURE the number of protons in an atom the number of protons and neutrons in an atom HeHe 22 44Atomic mass Atomic number number of electrons = number of protons
Editor's Notes
- #6: http://charm.physics.ucsb.edu/people/hnn/physicists.html