Chapter 5: The Periodic Table

History of the Periodic Table Dmitri Mendeleev published the first periodic table, based on increasing atomic masses of the elements Henry Moseley published the first periodic table, based on increasing atomic number. (Considered to be the first MODERN Periodic Table)

Figure 7.23 Mendeleev’s Early Periodic Table, Published in 1872

Mendeleev’s Table

Moseley’s Periodic Table

The four blocks of the Periodic Table: s, p, d, f

Different groups of elements 1) Alkali Metals 2) Alkaline-Earth Metals 3) Transition Metals 4) Metalloids 5) Chalcogens 6) Halogens 7) Noble Gases 8) Inner Transition Metals

Different groups of elements

Periodic Table

Groups- vertical columns. Elements of the same group tend to have similar chemical properties. Periods- horizontal rows, gives energy level of electrons. Representative Elements-all s & p block elements Periodic Table has 3 major types of elements: Metals, nonmetals, metalliods. (know where these are!)

Alkali Metals: group 1 metals luster(shiny) soft metals EXTREMELY REACTIVE (Produce hydrogen gas in water and cause severe explosions) All have only 1 valence electron

Alkali Metals: group 1 metals

Alkaline-Earth Metals: group 2 metals Have a luster harder than alkali metals More stable, less reactive than alkali metals All have 2 valence electrons.

Alkaline-Earth Metals: group 2 metals

Transition Metals

Transition Metals-groups 3-12 have luster harder and denser s-block metals More stable, less reactive than alkaline- earth metals Valence is unpredictable in most cases

Transition Metals-groups 3-12

Inner Transition Metal: f-block Metals Lanthanide Series-(Rare-Earth Metals) Elements: La(#57) through-Yb(#70) These Metals are rare. Actinide Series-(Radioactive Series) Elements: Ac(#89) through No(#102) All isotopes of these atoms are radioactive.

f-block metals

Other metals

Metalloids(semiconductors) Metalloids have both metallic and nonmetallic properties. Metalloids separate metals and nonmetals. Metalloids are used to make computer chips.

Metalloids(semiconductors)

Halogens-group 17 Halogens have 7 valence electrons. This makes them the most reactive NONMETALS. Fluorine atoms have the strongest electronegativity of all atoms(4.0), that is they have the strongest ability to attract electrons.

Noble Gases: group 18 These are the most stable, least reactive elements of the entire periodic table. They are practically unreactive. Their stability comes from having completely filled energy levels. They have either 2(helium) or 8(all others) valence electrons. Having 8 valence electrons is called a complete octet.