1. Isotopes

2. Isotopes of Magnesium Atomic symbol Mg Mg Mg Number of protons12 12 12 Number of electrons12 12 12 Mass number 24 25 26 Number of neutrons 12 13 14 24 12 25 12 26 12 Isotope Notation Mg-24 Mg-25 Mg-26 Timberlake, Chemistry 7 th Edition, page 64 12p + 12n 0 12p + 13n 0 12p + 14n 0 12e -

3. Isotopes of Hydrogen 1 p + 1 e - 1 p + 1 n 1 e - 1 p+ 2 n 1 e - ProtiumDeuteriumTritium (ordinary hydrogen) (heavy hydrogen)(radioactive hydrogen) Ralph A. Burns, Fundamentals of Chemistry 1999, page 100 H-2H-3H-1

4. Isotopes of Hydrogen ProtiumProtium (H-1) 1 proton, 0 neutrons, 1 electron most abundant isotope DeuteriumDeuterium (H-2) 1 proton, 1 neutron, 1 electron used in “heavy water” TritiumTritium (H-3) 1 proton, 2 neutrons, 1 electron radioactive 1 p + 1 e - 1 p + 1 n 1 e - 1 p+ 2 n 1 e -

5. Isotopes of Three Common Elements ElementSymbol Fractional Abundance Average Atomic Mass Carbon Chlorine Silicon Si 28 29 30 27.977 28.976 29.974 92.21% 4.70% 3.09% 12 6 13 6 35 17 37 17 28 14 29 14 30 14 12.01 35.45 28.09 1.11%13.003 13 C 99.89% 12 (exactly)12 C Mass (amu) 75.53% 24.47%36.96637Cl 34.96935Cl Mass Number LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World, 1996, page 110

6. Radioisotopes Radioactive isotopes Many uses –Medical diagnostics –Optimal composition of fertilizers –Abrasion studies in engines and tires Radioisotope is injected into the bloodstream to observe circulation.

7. Half-Life of Isotopes Isotope Half-Life Radiation emitted Half-Lives and Radiation of Some Naturally Occurring Radioisotopes Carbon-14 5.73 x 10 3 years  Potassium-40 1.25 x 10 9 years  Thorium-234 24.1 days  Radon-2223.8 days  Radium-2261.6 x 10 3 years  Thorium-230 7.54 x 10 4 years  Uranium-235 7.0 x 10 8 years  Uranium-2384.46 x 10 9 years 

8. Atomic Structure ATOMSATOMS –Differ by number of protons IONSIONS –Differ by number of electrons ISOTOPESISOTOPES –Differ by number of neutrons

9. Formation of Cation 11p + sodium atom Na e-e- loss of one valence electron e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- sodium ion Na + 11p + e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e-

10. Formation of Anion 17p + chlorine atom Cl e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- gain of one valence electron chloride ion Cl 1- 17p + e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e-

11. Formation of Ionic Bond chloride ion Cl 1- sodium ion Na + 11p + e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- 17p + e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e-

12. Formación de cationes 11p + Átomo de sodio Na e-e- pérdida de un Valence electrón e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- De iones de sodio Na + 11p + e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e-

13. Formación de aniones 17p + Átomo de cloro Cl e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- de ganancia un Valence electrón De iones de cloruro Cl 1- 17p + e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e-

14. Formación de Ionic Bond De iones de cloruro Cl 1- De iones de sodio Na + 11p + e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- 17p + e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e-

15. Ionic Bonding - - - - - -- - - - - -- - -- n = 2 Na [Ne]3s 1 n = 3 + - - - - - -- - - - -- - -- - Cl [Ne]3s 2 3p 5 Na + [Ne] Cl - [Ne]3s 2 3p 6 NaCl Transfer of electrons to achieve a stable octet (8 electrons in valence shell).

16. Covalent Bonding - - - - n = 1 O [He]2s 2 2p 4 n = 2 + - - - - - - - O2O2 Sharing of electrons to achieve a stable octet (8 electrons in valence shell). - - - - - - - - - - - - - - - - - O [He]2s 2 2p 4