General Chemistry 162 Flashcard
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Unlock answers| Representative Elements |
- The properties of the elements are determined by their electron configurations. - Electron configurations (and orbital properties) determine periodic trends: electron affinity, ionization energy, atomic size, metal vs nonmetal characteristics, bonding abilities. - Each group shares common properties and distinct differences based on electron configurations. |
Group 1A Elements
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H, alkali metals (Li, Na, K, Rb, Cs, Fr) - All but H are very active metals. - ns1 electron configuration (n=1 to 7) - Metals readily oxidized to X+ state. |
| Hydrides |
| Binary compounds containing H. |
| Ionic Hydrides |
| - Hydrogen combines with G1A or G2A metal; contains hydride ion and metal cation; H+ is strong reducing agent. |
Covalent Hydrides
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| Hydrogen combines with other nonmetals..HCl, CH4, etc. |
| Metallic (Interstitial) Hydrides |
| - Transition metal catalysts treated with H2 (g); H2 molecules dissociate at the metal surface and H atoms occupy holes in the crystal structure (potential use as a portable fuel). |
| Group 2A Elements |
- Alkaline earth metals: Be, Mg, Ca, Sr, Ba, Ra. - All are reactive metals (Be and Mg less reactive with water at 25 degrees Celsius). - ns2 electron configuration (n=2 to 7). - Readily oxidized to X2+ state. |
| Group 3A Elements |
- Nonmetallic (B), Metals (Al, Ga, In, Tl) - ns2p electron configuration (n=2 to 6). - Cannot achieve valence electron octets in neutral molecules. - B and Al form strong bonds to F and O. |
| Group 4A Elements |
- Nonmetallic (C), Metalloids (Si, Ge), Metals (Sn, Pb) - ns2p2 electron configuration (n=2 to 6) - Can achieve valence electron octets in neutral molecules. - All form covalent bonds with other nonmetals). |
| Group 5A Elements |
- Nonmetallic (N, P), Metalloid (As), Metals (Sb, Bi). - ns2p3 electron configuration (n=2 to 6). - Electronegativity decreases down the group. - Metallic character increases down the group.
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| Group 6A Elements |
- Nonmetallic (O, S, Se), Metalloids (Te, Po). - ns2p4 electron configuration (n=2 to 6). - Metallic properties increase down the column, but not G6A element behaves like a true metal. - Common behaviour: reaction with metal to become 2- ion in ionic compound; for most metals, most common minerals are oxides or sulfides. - Covalent bonds with other NMs; series of covalent hydrides (H2X). - All but O have d orbitals available, so more than an octet is common. - Te and Po can be 4+ cations, but with limited chemistry. |
| Group 7A Elements |
- Nonmetallic: F, Cl, Br, I, At. - ns2p5 electron configuration (n=2 to 6). - All are nonmetals. - Properties vary smoothly down the group, except for unexpectedly low E.A. of fluorine and small bond energy of F2. - Highly reactive, not found as free elements in nature, but rather as halide ions (X-) in minerals and seawater. - Highly electronegative..form polar covalent bonds with other NMs and ionic bonds with lower O.S. metals. - Compounds with metals in higher O.S. are polar covalent. |
| Group 8A Elements |
- Nonmetallic (He, Ne, Ar, Kr, Xe, Rn) - ns2p6 electron configuration (n=2 to 6)..full octet! - All are nonmetals. - All are very non-reactive, but some compounds can be formed. |
