10 CHEMICAL BONDING elements, and thus have a formal charge of -l in the tetrahedral anions BF4 and Alh respectively. LitH—Al F Sodium tetrafluoroborate Lithium aluminum hydride (c, d) Both of the tetrahedral anions have 32 valence electrons. Sulfur contributes 6 valence elec- trons and phosphorus 5 to the anions. Each oxygen contributes 6 electrons. The double negative charge in sulfate contributes 2 more, and the triple negative charge in phosphate Potassium sulfate Sodium phosphate The formal charge on each oxygen in both ions is-1. The formal charge on sulfur in sulfate is+2; the charge on phosphorus is +l. The net charge of sulfate ion is-2; the net charge of phosphate ion is-3 1.26(a) Each hydrogen has a formal charge of 0, as is always the case when hydrogen is covalently bonded to one substituent. Oxygen has an electron count of 5 H Electron count of oxygen=2+3(6)=5 Unshared Covalently A neutral oxygen atom has 6 valence electrons; therefore, oxygen in this species has a formal harge of +1. The species as a whole has a unit positive charge. It is the hydronium ion, HO b) The electron count of carbon is 5: there are 2 electrons in an unshared pair, and 3 electrons are ounted as carbon's share of the three covalent bonds to hydrogen Two electrons "owned"by carbon. One of the electrons in each C-h bond"belongs"to carbon An electron count of 5 is one more than that for a neutral carbon atom. The formal charge on carbon is -l, as is the net charge on this species (c) This species has 1 less electron than that of part(b). None of the atoms bears a formal charge The species is neutral. H-C-H Electron count of carbon =1+56=4 (d) The formal charge of carbon in this species is +l. Its only electrons are those in its three covalent bonds to hydrogen, and so its electron count is 3. This corresponds to l less electron than in a neutral carbon atom, giving it a unit positive charge Back Forward Main Menu TOC Study Guide Toc Student OLC MHHE Websiteelements, and thus have a formal charge of 1 in the tetrahedral anions BF4  and AlH4  respectively. (c, d) Both of the tetrahedral anions have 32 valence electrons. Sulfur contributes 6 valence elec￾trons and phosphorus 5 to the anions. Each oxygen contributes 6 electrons. The double negative charge in sulfate contributes 2 more, and the triple negative charge in phosphate contributes 3 more. The formal charge on each oxygen in both ions is 1. The formal charge on sulfur in sulfate is 2; the charge on phosphorus is 1. The net charge of sulfate ion is 2; the net charge of phosphate ion is 3. 1.26 (a) Each hydrogen has a formal charge of 0, as is always the case when hydrogen is covalently bonded to one substituent. Oxygen has an electron count of 5. A neutral oxygen atom has 6 valence electrons; therefore, oxygen in this species has a formal charge of 1. The species as a whole has a unit positive charge. It is the hydronium ion, H3O. (b) The electron count of carbon is 5; there are 2 electrons in an unshared pair, and 3 electrons are counted as carbon’s share of the three covalent bonds to hydrogen. An electron count of 5 is one more than that for a neutral carbon atom. The formal charge on carbon is 1, as is the net charge on this species. (c) This species has 1 less electron than that of part (b). None of the atoms bears a formal charge. The species is neutral. (d) The formal charge of carbon in this species is 1. Its only electrons are those in its three covalent bonds to hydrogen, and so its electron count is 3. This corresponds to 1 less electron than in a neutral carbon atom, giving it a unit positive charge. Electron count of carbon 1 (6) 4 1 H C 2 H H Unshared electron Electrons shared in covalent bonds H H C H Two electrons “owned” by carbon. One of the electrons in each C H bond “belongs” to carbon. H O H H Electron count of oxygen 2 (6) 5 1 2 Unshared pair Covalently bonded electrons S2 O O Potassium sulfate 2K O    O  P O O O Sodium phosphate 3Na O     B F F F Na F Al H H H Li H Sodium tetrafluoroborate Lithium aluminum hydride   10 CHEMICAL BONDING Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website