1. POD Who were the major scientists involved in discovering the model of the atom?

3. Topic 2 – Atomic Structure 2.1 – The nuclear atom SWBAT: Use nuclear symbol notation to deduce the # of protons, neutrons, & electrons in atoms and ions Calculate non-integer relative atomic masses and abundances of isotopes from given data, including mass spectra

4. Dalton’s Atomic Theory All matter is composed of tiny indivisible particles called atoms Atoms cannot be created or destroyed Atoms of the same element are like in every way Atoms of different elements are different Atoms can combine together in small #’s to form molecules

5. Atoms have electrons JJ Thomson discovered different metals produce a stream of negatively charged particles when high voltage is applied across 2 electrodes These particles were the same regardless of the metal, he suggested they make up all atoms  electrons JJ Thomson’s plum pudding model

6. Rutherford’s model Gold foil experiment showed Thomson’s model was incorrect Rutherford suggested atoms are mostly empty space with a small dense positively charged nucleus

7. Sub-atomic particles Protons & neutrons are called nucleons because they reside in the nucleus

8. Bohr’s model of the atom He imagined atoms as a small solar system where electrons orbit the positively charged nucleus Neutrons are needed to stabilize the nucleus of atoms having more than 1 proton

9. Atomic # & Mass # Atomic # = number of protons, determines the position in the periodic table Mass # = protons + neutrons

10. Isotopes Atoms of the same element with different # of neutrons The average mass of an element takes into account all its isotopes and their abundances Average atomic mass=(isotope mass * % abundance) + (isotope mass * % abundance) + (isotope mass * % abundance)….

13. Mass Spectrometer A mass spectrometer can measure the mass of individual atoms https://www.youtube.com/watch?v=J-wao0O0_qM

14. Mass Spectra The results from the mass spectrometer give a mass spectrum

15. Mass Spectra

16. Calculate the average mass of chlorine using this data