CHAPTER ONE Chemical Bonding 2p FIGURE 1.4 Boundary surfaces of the 2p s. The wave function changes sign at the ne is a nodal surface for the 2p, orbit and the xy-plane is a nodal surface for the 2p, orbital as Hunds rule. Of particular importance in Table 1. are hydrogen, carbon, nitrogen, and oxygen. Countless organic compounds contain nitrogen, oxygen, or both in addition to car bon, the essential element of organic chemistry. Most of them also contain hydrogen It is often convenient to speak of the valence electrons of an atom. These are the outermost electrons, the ones most likely to be involved in chemical bonding and reac tions. For second-row elements these are the 2s and 2p electrons. Because four orbitals (25, 2pr 2p, 2p,) are involved, the um number of electrons in the valence shell of any second-row element is 8. Neon, with all its 2s and 2p orbitals doubly occupied, has eight valence electrons and completes the second row of the periodic table Answers to all problems that PROBLEM 1.1 How many valence electrons does carbon have? appear within the body of a cs 2. A brief discussion of Once the 2s and 2p orbitals are filled, the next level is the 3s, followed by the 3po 3p nd 3p, orbitals. Electrons in these orbitals are farther from the nucleus than those in the ow to do problems of the same type are offered in the 2s and 2p orbitals and are of higher energy Study Guid TABLE 1.1 Electron Configurations of the First Twelve Elements of the Periodic Table Number of electrons in indicated orbital Atomi Element number z 1s 25 批m oron 12345678 Fluorine Neon 10 122222222222 1222222222 Sodium 22222 222 2 Magnesium 12 Back Forward Main MenuToc Study Guide ToC Student o MHHE Websiteas Hund’s rule. Of particular importance in Table 1.1 are hydrogen, carbon, nitrogen, and oxygen. Countless organic compounds contain nitrogen, oxygen, or both in addition to car￾bon, the essential element of organic chemistry. Most of them also contain hydrogen. It is often convenient to speak of the valence electrons of an atom. These are the outermost electrons, the ones most likely to be involved in chemical bonding and reac￾tions. For second-row elements these are the 2s and 2p electrons. Because four orbitals (2s, 2px, 2py, 2pz) are involved, the maximum number of electrons in the valence shell of any second-row element is 8. Neon, with all its 2s and 2p orbitals doubly occupied, has eight valence electrons and completes the second row of the periodic table. PROBLEM 1.1 How many valence electrons does carbon have? Once the 2s and 2p orbitals are filled, the next level is the 3s, followed by the 3px, 3py, and 3pz orbitals. Electrons in these orbitals are farther from the nucleus than those in the 2s and 2p orbitals and are of higher energy. 10 CHAPTER ONE Chemical Bonding x xx z y yy zz 2px 2pz 2py FIGURE 1.4 Boundary surfaces of the 2p orbitals. The wave function changes sign at the nucleus. The yz-plane is a nodal surface for the 2px orbital. The probability of finding a 2px electron in the yz-plane is zero. Analogously, the xz-plane is a nodal surface for the 2py orbital, and the xy-plane is a nodal surface for the 2pz orbital. TABLE 1.1 Electron Configurations of the First Twelve Elements of the Periodic Table Number of electrons in indicated orbital Element Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Atomic number Z 1 2 3 4 5 6 7 8 9 10 11 12 1s 1 2 2 2 2 2 2 2 2 2 2 2 2s 1 2 2 2 2 2 2 2 2 2 2px 1 1 1 2 2 2 2 2 2py 1 1 1 2 2 2 2 2pz 1 1 1 2 2 2 3s 1 2 Answers to all problems that appear within the body of a chapter are found in Appen￾dix 2. A brief discussion of the problem and advice on how to do problems of the same type are offered in the Study Guide. Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website