Atomic structure
- 2. How are atoms studied? Atoms are the building blocks of matter Atoms are too small in size to study easily Size of Earth : soda can = soda can : atom
- 3. What is the Structureof an atom? Nucleus – center of the atom Home of Protons and Neutrons Proton Has a positive (+) charge Has a relative mass of 1 Determines the atomic number Found inside the nucleus
- 4. What Is The Structure Of An Atom? Neutron Has no (0) charge Has a relative mass of 1 Determines the isotope Isotopes are two of the same element with different masses Found inside the nucleus
- 5. What Is The Structure Of An Atom? Electron Has a negative (-) charge Has a relative mass of 0 (zero) Determines the ion Found outside the nucleus Bohr model – electrons are in specific energy levels Electron cloud model – electrons are in a random cloud
- 6. Atomic Structure Neutral atoms have the same number of protons and electrons. Ions are charged atoms. cations – have more protons than electrons and are positively charged anions – have more electrons than protons and are negatively charged
- 7. ATOMIC STRUCTURE Particle proton neutron electron Charge + ve charge -ve charge No charge 1 1 nil Mass
- 8. How are P, N, e- related? No. of protons = atomic number No. of electrons = No. of protons in a neutral atom No. of protons + No. of neutrons = atomic mass
- 9. Can you guess these persons??
- 10. HISTORY OF THE ATOM 460 BC Democritus develops the idea of atoms He Pounded Up Materials In His Pestle And Mortar Until He Had Reduced Them To Smaller And Smaller Particles Which He Called ATOMA (greek for indivisible)
- 11. HISTORY OF THE ATOM 1808 John Dalton suggested that all matter was made up of tiny spheres that were able to bounce around with perfect elasticity and called them ATOMS
- 12. 8 X2Y16 X 8 Y+ DALTONS ATOMIC THEORY
- 13. HISTORY OF THE ATOM 1898 Joseph John Thompson found that atoms could sometimes eject a far smaller negative particle which he called an ELECTRON
- 14. Plum Pudding model of an atom.
- 15. Results of foil experiment if Plum Pudding model had been correct.
- 16. Actual Results.
- 17. J.J. Thomson, measured mass/charge of e- (1906 Nobel Prize in Physics) A = alpha B = gamma C = beta
- 18. HISTORY OF THE ATOM Thompson develops the idea that an atom was made up of electrons scattered unevenly within an elastic sphere surrounded by a soup of positive charge to balance the electron's charge 1904 like plums surrounded by pudding. PLUM PUDDING MODEL
- 19. HISTORY OF THE ATOM 1910 Ernest Rutherford oversaw Geiger and Marsden carrying out his famous experiment. they fired Helium nuclei at a piece of gold foil which was only a few atoms thick. they found that although most of them passed through. About 1 in 10,000 hit
- 20. HISTORY OF THE ATOM gold foil helium nuclei They found that while most of the helium nuclei passed through the foil, a small number were deflected and, to their surprise, some helium nuclei bounced straight back. helium nuclei
- 21. HISTORY OF THE ATOM Rutherford’s new evidence allowed him to propose a more detailed model with a central nucleus. He suggested that the positive charge was all in a central nucleus. With this holding the electrons in place by electrical attraction However, this was not the end of the story.
- 23. HISTORY OF THE ATOM 1913 Niels Bohr studied under Rutherford at the Victoria University in Manchester. Bohr refined Rutherford's idea by adding that the electrons were in orbits. Rather like planets orbiting the sun. With each orbit only able to contain a set number of electrons.
- 24. The Bohr Model of the Atom
- 25. The Bohr’s Model
- 26. I’m an electron! I’m a proton! I’m a neutron!
- 27. I was walking along and I saw these two. I was telling jokes to the neutron. The proton and I were having fun.
- 28. They looked so happy there together. I was p o s i t i v e l y charged! I couldn’t have amassed more happiness.
- 29. The proton looked happy, so I wandered closer. I could see the electron coming near. The who? Huh?
- 30. They were HUGE next to me! The electron was so cute! Like a speck of dust, or something…
- 31. I didn’t want to seem obvious, so I kept walking. Around and around the electron goes. Hey electron, you’re making the proton dizzy.
- 32. The proton seems so happy with the neutron. I’m having fun, but I still notice the electron. It won’t bother me if the electron hangs around.
- 33. I guess I’ll just wander around out here. I’m happy hanging out here. The center is cool, but sometimes it can be a “Bohr”.
- 34. Electrons circle around the nucleus of an atom. Protons are a main part of the nucleus of an atom. Neutrons also hang out in the nucleus of an atom.
- 35. Electrons have a negative charge. Protons have a positive charge. + Neutrons have no charge. 0
- 36. Electrons are little and have a mass of almost zero. Protons are big and have a mass of one. Neutrons are also big and have a mass of one.
- 38. Subatomic Particles Particle Mass (g) Charge (Coulombs) Charge (units) Electron (e- ) 9.1 x 10-28 -1.6 x 10-19 -1 Proton (p) 1.67 x 10-24 +1.6 x 10-19 +1 Neutron (n) 1.67 x 10-24 0 0 mass p = mass n = 1840 x mass e-
- 39. Atomic Structure
- 40. SUMMARY 1. The Atomic Number of an atom = number of protons in the nucleus. 2. The Atomic Mass of an atom = number of Protons + Neutrons in the nucleus. 3. The number of Protons = Number of Electrons. 4. Electrons orbit the nucleus in shells. 5. Each shell can only carry a set number of electrons.