Chapter 14: Chemical Periodicity

1. Chapter 14: Chemical Periodicity

2. The Periodic TableMendeleev website • Russian chemist Dmitri Mendeleev is credited with making the basis for the periodic table that is still used today. • Periodic table shows atomic number, atomic mass, element name, element symbol, and amount of electrons in each energy level.

3. Metals vs. Non-metals: Characteristics MetalsNon-Metals *Lose Electrons *Gain electrons *Conductors of electricity *Poor conductors of electricity *Conductors of heat * Poor conductors of heat *Luster *Lack luster *Malleable *Non-malleable

4. Alloys • Alloys-mixtures composed of two or more elements at least one of which is a metal • Alloys are prepared by melting the mixture of the ingredients and then cooling the mixture • Brass is an alloy of copper and zinc • Bronze is an alloy of 7 parts copper and one part tin • Steel is an alloy of iron and carbon. It is corrosion resistant ductile, hard and tough.

5. Alloy Properties • Shows an alloy mixture. It is NOT a compound but a physical mixing of a metal plus at least one other material (shown by red circle, it can be another metal eg Ni, a non-metal eg C or a compound of carbon or manganese, and it can be bigger or smaller than iron atoms). Many alloys are produced to give a stronger metal. The presence of the other atoms (smaller or bigger) disrupts the symmetry of the layers and reduces the 'slip ability' of one layer next to another. The result is a stronger harder less malleable metal.

6. Alloy Properties

7. The Noble Gases • The noble gases include helium, neon, argon, and krypton. • These are elements in which the outermost s and p sublevels are filled. • Also called inert gases because they do not participate in many chemical reactions.

8. The Representative Elements • The representative elements outermost s or p sublevels are only partially filled. • Blocks S and P in the diagram. • There are three groups of representative elements: the alkali metals, the alkaline earth metals, and the halogens.

9. The Transition Metals • The transition metals are metallic elements in which the outermost s sublevel and nearby d sublevel contain electrons. • Such metals include iron, copper, gold, silver, nickel, zinc and many others.

10. The Inner Transition Metals • The inner transition metals are metallic elements in which the outermost s sublevel and nearby f sublevel generally contain electrons. • Such metals include uranium, plutonium, actinium, and many others.

11. Websites of Metals • History of Metals • Transition metal info.

12. ElectronConfiguration • Noble Gases: • Helium: 1s2 • Neon: 1s22s22p6 • Argon: 1s22s22p63s23p6 • Krypton: 1s22s22p63s23p63d104s24p6

13. Electron Configurations • The electron configuration is the arrangement of electrons around the nucleus of an atom in its ground state. • Here are some examples of electron configurations: Fe: 1s22s22p63s23p64s23d6 Mg: 1s22s22p63s2

14. Ionization energy • The energy needed to remove an electron from an atom.

15. Ionization Energies and Trends The energy required to remove an electron from a gaseous atom. Moving left to right on the periodic table, ionization energy increases. Moving down a group in the periodic table, ionization energy decreases. Moving left to right on the periodic table, electron affinity increases. ElementGroup1st2nd3rd4th5th6th A 1086 2352 4621 6223 37832 47279 A 520 7298 11815 A 899 1752 14849 21007 25114 A 1312

16. Ionization Energy • The energy required to overcome the attraction of the nuclear charge and remove an electron from a gaseous atom. • Removing one electron results in the formation of a positive ion, 1+ charge.

17. Electronegativity • The ability of an atom to attract electrons when forming bonds.

18. Electronegativity Values-use to determine bond type

19. Additional Information • Electronegativity and Shielding Effect • __________related. This means that when one repels an electron, the other attracts an electron. • Shielding Effect is ____________related to Ionization Energy • Electron Affinity is __________related to shielding effect • Ionization energy is __________related to shielding effect • Electron Affinity (attraction for electrons) • Fluorine has the most electronegativity • Lithium has the least amount of electronegativity • Group 7 on the periodic table wants to gain one electron. That group has the highest electronegativity.

20. Shielding Effect • Electron levels act like shields. • They shield all other electrons from the nucleus • Result : larger elements lose electrons easier

21. Shielding Effect

22. Atomic Radius / Ionic Radius • Atomic Radius - The size of an atom before reacting • Ionic Radius -The size of an atom after reacting • (Reacting refers to the loss or gain of an electron) e - Li 152 Li+ 60

23. Atomic vs. Ionic Radii

24. Atomic/Ionic Radius • Atomic Radius: the size of an atom before reacting. • Ionic Radius: the size of an atom after reacting.

25. Periodic Trends Periodic Trends refer to the varyingproperties that are relative to your direction going across and down the periodic table. …These varying properties include... Atomic Radius Ionic Size Ionization Energy Nuclear Charge Shielding Effect Electronegativity

26. Nuclear charge increases Shielding is constant Atomic Radius decreases Ionization Energy increases Electronegativity increases Nuclear charge increases Shielding increases Atomic Radius increases Ionic size increases Ionization Energy decreases Electronegativity decreases Periodic Table

27. The End