Representative Elements Chapter 19

Anderson Kuo
Period 1

CHAPTER 19 – The Representative Elements: Groups 1A through 4A

-19.1- A Survey of the Representative Elements

I. Elements

A. Representative Elements: Groups 1A through 8A ← Filling s and p orbitals ← First member of a group forms the strongest ( bonds; results in diatomic molecules

B. Transition Elements: center of the table ← Filling d orbitals

C. Lanthanides & Actinides: listed separately, on the bottom on the table ← Filling 4f and 5f orbitals

II. Metals/Nonmetals/Metalloids

A. Metals: ← Lose valence electrons to form cations ← Exhibiting valence electron configuration of the noble gas from the preceding period ← Metallic character increases going
Carbon Family ← ns2np2 valence-electron configuration ← contains two of the most important elements on earth: • carbon, the fundamental constituent of the molecules necessary for life, and silicon, which forms the basis of the geologic world ← lighter members are nonmetals; heavier metals are metals • all group members can form covalent bonds to nonmetals

B. Carbon ← Carbon compounds cannot react with Lewis bases to form two additional covalent bonds b/c of the small atomic size of carbon and because there are no d orbitals on carbon to accommodate the extra electrons ← Occurs in the earth’s crust mainly in two allotropic forms – graphite and diamond ← Carbon dioxide is a product of human and animal respiration and of the combustion of fossil fuels; produced by fermentation

C. Silicon ← Second most abundant element in the earth’s crust ← Approximately 85% of the earth’s crust is composed of silica and silicates ← Majorly used in semiconductors for electronic devices

D. Germanium ← Relatively rare element ← A semimetal used mainly in the manufacture of semiconductors for transistors and similar electronic