2. ATOMIC NUMBER

3. The atomic number of an element is the number of protons in the nucleus of that element. The atomic number of an element is the number of protons in the nucleus of that element. The atomic number determines the identity of the atom. The atomic number determines the identity of the atom.

4. Location of Subatomic Particles

5. Protons and Neutrons lie in the Nucleus Protons and Neutrons lie in the Nucleus Electron lie outside the nucleus Electron lie outside the nucleus P & N E nucleus E = electron P = Proton N = Neutron

6. Atoms of the same element can have different masses. Atoms of the same element can have different masses. They have the same number of protons and electrons but different numbers of neutrons. They have the same number of protons and electrons but different numbers of neutrons. These atoms are called isotopes of the element. These atoms are called isotopes of the element.

8. Examples of Isotopes ElementProtonsElectronsNeutronsSymbol Hydrogen 110 1 1 H Hydrogen 111 1 2 H Hydrogen 112 1 3 H Uranium 9292 143 92 235 U Uranium 9292 146 92 238 U Chlorine 171718 17 35 Cl Chlorine 171720 17 37 Cl

9. BOHR MODEL OF THE ATOM Niels Bohr knew that light was absorbed and emitted by atoms. Niels Bohr knew that light was absorbed and emitted by atoms. He used ideas and principles from Quantum Mechanics to suggest a model of the hydrogen atom. He used ideas and principles from Quantum Mechanics to suggest a model of the hydrogen atom. The orbits of an electron in atom are quantized which means that each orbit corresponds to a fixed energy.Electrons that travel in these orbits are stable and do not emit light. The orbits of an electron in atom are quantized which means that each orbit corresponds to a fixed energy.Electrons that travel in these orbits are stable and do not emit light. Light is emitted or absorbed when an electron jumps from one orbit to another. Light is emitted or absorbed when an electron jumps from one orbit to another.

10. Electron Orbitals

11. The orbits were later called shells and then even later energy levels. The orbits were later called shells and then even later energy levels. Electrons tend to fill the energy levels closest to the nucleus first. Electrons tend to fill the energy levels closest to the nucleus first. The maximum number of electron in any energy level is given by 2n 2 The maximum number of electron in any energy level is given by 2n 2

12. When an electron jumps from the lowest energy level to a higher level, light is absorbed by the atom. When an electron jumps from the lowest energy level to a higher level, light is absorbed by the atom. When an electron jumps from a higher energy level to a lower energy light is emitted by the atom. When an electron jumps from a higher energy level to a lower energy light is emitted by the atom. Bohr's model explained the emission spectrum of hydrogen. Bohr's model explained the emission spectrum of hydrogen.

13. ShellSubshellEnergy Level Max # of Electrons K s1 2 (1s 2 ) L s, p2 8 (2s 2 2p 6 ) M s,p,d3 18 (3s 2 3p 6 3d 10 ) N s,p,d,f4 32 (4s 2 4p 6 4d 10 4f 14 ) Think of the shells as the floors in an apartment building. Think of the subshells as the different apartments on each floor. For example on the 1 st Floor, all you have is apartment 1s. On the 2 nd Floor you have apartment 2s and 2p. On the 3 rd Floor you have apartment 3s, 3p and 3d. On the 4 th Floor you have apartment 4s, 4p and 4d and 4f. Apartment s can hold 2 people (electrons), Apartment p can hold six people (electrons), Apartment d can Hold 10 people (electrons) andApartment f can hold 14 people (electrons)

14. max =2 max = 8 Simplified Electron Configuration (CHM02) (1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 0 )

15. Electron Structures Using the Bohr Model ElementElectron Group Period Structure 1 H1 (1s 1 ) I 1 2 He2 (1s 2 ) II 1 3 Li2-1 (1s 2 2s 1 ) I 2 4 Be2-2 (1s 2 2s 2 ) II 2 5 B2-3 (1s 2 2s 2 2p 1 ) III 2 6 C2-4 (1s 2 2s 2 2p 2 ) IV 2 7 N2-5 (1s 2 2s 2 2p 3 ) V 2 8 O2-6 (1s 2 2s 2 2p 4 ) VI 2 9 F2-7 (1s 2 2s 2 2p 5 ) VII 2 10 Ne2-8 (1s 2 2s 2 2p 6 ) VIII 2 18 Ar2-8-8 (1s 2 2s 2 2p 6 3s 2 3p 6 ) VIII 3 20 Ca2-8-8-2 (1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 ) II 4

16. LEWIS STRUCTURES OF ATOMS Valence electrons are the outermost electrons of an atom. Valence electrons are the outermost electrons of an atom. Na with the electron structure 2-8-1, has 1 valence electron. Na with the electron structure 2-8-1, has 1 valence electron. Fluorine with the electron structure 2-7 has 7 valence electrons Fluorine with the electron structure 2-7 has 7 valence electrons In a Lewis Structure of an atom, dots are used to show the valence electrons of atoms. In a Lewis Structure of an atom, dots are used to show the valence electrons of atoms.

17. A capital letter represents the nucleus of the atoms a A capital letter represents the nucleus of the atoms a When writing Lewis structures, imagine each symbol to be enclosed in a square. When writing Lewis structures, imagine each symbol to be enclosed in a square. The electron dot structures are obtained by adding the first two electrons to one corner. Add the remaining electrons to a side until all of the valence electrons are shown The electron dot structures are obtained by adding the first two electrons to one corner. Add the remaining electrons to a side until all of the valence electrons are shown F F FFFFFF

18. Aluminum has 3 valence electrons: Aluminum has 3 valence electrons: Oxygen has 6 valence electrons Oxygen has 6 valence electrons Al O

19. Lewis Octet Rule All atoms with the exception of hydrogen tend to form bonds until they have 8 electrons in the outer shell. All atoms with the exception of hydrogen tend to form bonds until they have 8 electrons in the outer shell. All atoms have zero charge because they contain equal numbers of protons and electrons All atoms have zero charge because they contain equal numbers of protons and electrons Sodium (Na) 11 electrons+11 protons 11(-1)+11(+1)=0 Calcium (Ca) 20 electrons+20 protons 20(-1)+20(+1)=0

20. Formation of Ions An ion is a charged particle. An ion is a charged particle. It is formed by either adding or removing electrons from an atom. It is formed by either adding or removing electrons from an atom. Adding electrons to an atom results in the formation of negative ions (i.e., anion). Adding electrons to an atom results in the formation of negative ions (i.e., anion). Removal of electrons from an atom results in the formation of a positive ion (i.e., cation). Removal of electrons from an atom results in the formation of a positive ion (i.e., cation).

21. Formation of Anions Cl + e -  Cl - O + 2e -  O 2- N + 3e -  N 3-

22. Formation of Cations Na  Na + + e - Ca  Ca 2+ + 2e - Li  Li + + e -

23. The Ionic Bond An ionic bond results from the attraction between positive and negative ions. An ionic bond results from the attraction between positive and negative ions. Positive and negative ions result from electron transfer. Positive and negative ions result from electron transfer.

24. Periodic Table Location and Ionic Charge The charge on an ion can be predicted from the position of an element in the periodic table for A family elements. The charge on an ion can be predicted from the position of an element in the periodic table for A family elements. Group IAIIAIIIAIVAVAVIAVIIAVIIIA Charge +1+2 +3 -3 -2 -1 0