Periodic Table

1. Periodic Table

3. The Periodic Table • Historical development of the periodic table: Highlights • Mendeleev (1869): Put the elements into columns according to their properties. Generally ranked elements by increasing atomic mass. • Other guys: Pretty much did the same thing

4. Metals • These are general properties and may not be true for all metals. • Malleable: Can be pounded into sheets. • Ductile: Can be drawn into wires • Good conductors of heat and electricity • High density (usually) • High MP and BP (usually) • Shiny • Hard

5. Nonmetals: • Bonds between the atoms are highly localized, causing each of the properties below. Again, these are general properties and may not be true for all nonmetals. • Brittle • Poor conductors of heat and electricity • Low density • Low Melting Point and Boiling Point (many are gases!)

6. Metalloids: • The bonding in metalloids is between that of metals and nonmetals, so metalloids have properties of both. • Some metalloids are shiny (silicon), some are not (gallium) • Metalloids tend to be brittle, as are nonmetals. • Metalloids tend to have high MP and BP like metals. • Metalloids tend to have high density, like metals. • Metalloids are semiconductors of electricity – somewhere between metals and nonmetals. This makes them good for manufacturing computer chips.

7. Families/groups(the terms are synonymous and will be used interchangeably) • These are elements in the same columns of the periodic table.  • Elements within families/groups tend to have similar physical and chemical properties. • They have similar chemical and physical properties because they have similar electron configurations.

8. Periods: • Elements in the same rows of the periodic table • Elements in the same period have valence electrons in the same energy levels as one another. • Though you’d think this was important, it has very little effect on making the properties of the elements within a period similar to one another. • The closer elements are to each other in the same period, the closer are their chemical and physical properties.

9. Other fun locales in the periodic table: • Main block elements: These are the s- and p- sections of the periodic table (groups 1,2, 13-18) • Transition elements: These are the elements in the d- and f-blocks of the periodic table. • The term “transition element”, while technically referring to the d- and f-blocks, usually refers only to the d-block. • Technically, the d-block elements are the “outer transition elements” • Technically, the f-block elements are the “inner transition elements”

10. Major families in the periodic table: • Label these on your periodic table if they are not already labeled.

11. Families/groups

12. Alkali Metals • Group 1 (except for hydrogen) – • Most reactive group of metals • Flammable in air and water • Form ions with +1 charge • Low MP and BP (MP of Li = 181º C, Na = 98º C) • Soft (Na can be cut with a knife) • Low density (Li = 0.535, Na = 0.968)

13. Alkaline Earth Metals • Group 2: • Reactive, but less so than alkali metals • React in air and water (show Ca reacting in water) • Form ions with +2 charge • Low MP and BP, but higher than alkali metals (MP of Ba= 302º C, Mg = 649ºC • Soft, but harder than alkali metals • Low density, but higher than that of alkali metals (Ca = 1.55, Mg = 1.74).

14. (Outer) Transition Metals • Groups 3-12: • Note: These are general properties and may vary from transition metal to transition metal! There are many exceptions to each of these rules! • Stable and unreactive. • Hard • High MP and BP (Fe = 1535º C, Ti = 1660º C). • High density (Fe = 7.87, Ir = 22.4) • Form ions with various positive charges (usually include +2 and several others) • Used for high strength/hardness applications, electrical wiring, jewelry

15. Lanthanides and Actinides – The Inner Transition Metals • Lanthanides (4f section) • Also called the rare earth metals, because they’re rare. • Usually intermediate in reactivity between alkaline earth metals and transition metals. • High MP and BP • Used in light bulbs and TV screens as phosphors. • Actinides (5f section) • Many have high densities • Most are radioactive and manmade • Melting points vary, but usually higher than alkaline earth metals. • Reactivity varies greatly • Used for nuclear power/weapons, radiation therapy, fire alarms.

16. Group 17: Halogens • The most highly reactive nonmetals. • Highly volatile – F and Cl are gases, Br is a volatile liquid, and I is an easily sublimed solid. • Strong oxidizers – they readily pull electrons from other atoms. • Diatomic – form molecules with formula of X2 • Form ions with -1 charge • Used in water treatment and chemical production – Cl2 was used as a chemical weapon in World War I.

17. Group 18: Noble Gases • Highly nonreactive • Used to provide the atmosphere in situations where you don’t want chemical reactions to occur (light bulbs, glove boxes, etc).

18. Hydrogen – “The Weirdo” • Has properties unlike any other element • Diatomic – H2 • Can form either a +1 or -1 charge • Relatively nonreactive unless energy is added (under most conditions) – it can form explosive mixtures with oxygen (as it did in the Hindenburg explosion)