1. The Atom What to look for: Three Essential Questions E. Q. #1 = What are the parts of an atom? E. Q. #2 = In what manner can subatomic particles be differentiated? E. Q. #3 = How does the atomic structure impact chemical change & reactivity?

2. The Building Block of Matter  400 BC Democritus (_______ Philosopher)  Atomos = “_______________”  …like a brick is used to build a __________; an atom is used to build all matter…

3. First Atomic Theory  ________ (yr) John Dalton (__________ Chemist)  Using experiments formulates the first ______________ theory 1.All elements are composed of indivisible particles called __________ 2.________ of the same elements are exactly the same 3.________ of different elements are different 4.Two or more ______________ combine to form compounds

4. Subatomic Particles  The idea that the ________ was not a solid sphere, but a composition of small particles which came to be known as ______________ ________________ (2 words)  Julius Plucker, William Crooks & J J Thomson  _________________

5. J J Thomson ________ Discovers the electron ________ Discovers the electron First of the subatomic particles to be discovered. First of the subatomic particles to be discovered.

6. Ernest Rutherford (___________Physicist)  Gold Foil Experiments  ________ Discovers that the atom is mostly empty space  Later, he discovers a hard, dense center of the atom called the ______________

7. The Gold Foil Experiment

8. The _______ is mostly empty space  Most of the _____________ passed straight through to gold foil.  First important discovery by Rutherford

9. The NUCLEUS is Discovered  _______ Rutherford proves that the particles that do not pass through are hitting a small, dense ______ of the atom called the nucleus.  ____________ later goes on to discover the proton

10. 3 2 1 Name three major discoveries made by Ernest Rutherford & the Gold Foil Experiment : 1. _______________________________________ 2. _______________________________________ 3. _______________________________________ What are the two results of firing particle at atoms in the foil of the Gold Foil Experiments : 1. _______________________________________ 2. _______________________________________ Who was the first to attempt to form a complete atomic theory? 1. _______________________________________

11. Electron ____________ Levels  _______ Niels Bohr (_________ physicist) discovers the electrons travel around the outside of the atom on different energy levels  The Bohr Model = “solar ___________” model

12. The ___________ is Found  ________ James Chadwick proves the existence of the neutron.  Only ______ years later the neutron is used to split the first atom  Why was the neutron’s existence more difficult to prove?  What evidence hinted of its existence? “the missing mass” E. Q. #1 = What are the parts of an atom?

13. The Subatomic Particles ParticleLocation Mass (AMU) Charge Electron Proton Neutron E. Q. #2 = in what manner can subatomic particles be differentiated?

14. Finding the Number of _____________ Particles in an Atom  Atomic Number = the __________ of protons in the nucleus of an atom  Identifies each element  ____________ is #1 and it has 1 proton in its nucleus (only hydrogen has 1 proton)  ____________ is #2 and it has ___ protons in its nucleus (only helium has ____ protons)

15. # of Electrons  IF the atom is neutral (______ number positive charges as negative charges) then the number of electrons will be the same as protons.  ION = a charged atom (unequal number of protons and electrons)  +1 charge = the atom LOST ______ electron  -1 charge = the atom GAINED _____ electron  +2 charge = LOST _____ electrons  -2 charge = GAINED ____ electrons and so on

16. Example of Ions  Sodium will lose _____ electron when it bonds  Na +1 or Na +  Sodium’s atomic number is 11, so it has 11 ________________.  The +1 charge means Na +1 has ____ electrons

17. Another Example  Chlorine will gain an _______ when it bonds  Cl -1 or Cl -  Chlorine’s atomic number is 17, so it has 17 ____________  The -1 charge means Cl -1 has ____ electrons

18. ________ Number  The _____ subatomic particles that have mass?  Proton ____ neutron, both found in the nucleus  Mass Number = # of Protons + # of Neutrons  Mass # - Atomic # = # of neutrons

19. Practice Problems SymbolAtomic Number NumberMass ChargeProtonsNeutronsElectrons Mg1224 K1939 Na +1 1123 F -1 919 Mg +2 1224 Do Parts of the Atom & Atomic Structure practice sheet now.

20. ISOTOPES  Atoms of the same element with a different number of neutrons.  Ex: carbon-12 & carbon-14  Carbon- ______ 1. ___ protons 2. ___ neutrons 3. ___ electrons  Carbon- ______ 1. ___ protons 2. ___ neutrons 3. ___ electrons

21. Isotopes of Hydrogen  Hydrogen-1 (protium) 0 __________  Hydrogen-2 (deuterium) 1 __________  Hydrogen-3 (tritium) 2 __________

22. The ELECTRON ______________  The electron cloud is separated by different energy __________.  Electrons with less ________ travel on the levels closest to the nucleus.  Energy ________ are divided into sub-levels  Sub-levels are divided into orbitals  All of these _________, sub-levels & orbitals can overlap.

23. VALENCE ELECTRONS  Valence electrons = the outermost electrons  The ___________ involved in bonding  Determines the _________ properties of an atom Do What Is This Atom Now? Practice sheets 1 & 2 now. E. Q. #3 = How does the atomic structure impact chemical change & reactivity?

24. More about Electrons  Maximum # of electrons on each energy level  Level ____ = 2 electrons  Level ____ = 8 electrons  Level ____ = 18 electrons  Level ____ = 32 electrons

25. the Stable ______ the Stable ______  Due to the overlapping levels, sub-levels and orbitals the maximum number of outer most electrons is _____________.  An atom is becomes stable when it outer-most energy levels is ________ of electrons  This explains the chemical bonding properties of the _____________  _________ will do one of three things in order to fill their outer most energy levels. 1. gain electrons 2. lose electrons 3. share electrons

26. Concepts Coming Up Next  The number of valence electrons an atom has determines the group it becomes to on the _______________ _____________.  Groups or families of elements on the periodic table has similar ______________ properties.

27.  Valence ____________ determine how atoms will bond with other atoms in order to complete their outer-most energy level.  The Stable ______  CHEMICAL _____________  Ionic bonding (gaining/losing of electrons)  Covalent bonding (sharing of electrons) Concepts Coming Up Next