Which of the following molecules would you expect to have a dipole moment of zero To

Chapter 1, Problem 45

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Which of the following molecules would you expect to have a dipole moment of zero? To answer parts g and h, you may need to review the Strategy on page 42. a. CH 3 CH 3 Electrons are assigned to orbitals (atomic or molecular) following the aufbau principle, the Pauli exclusion principle, and Hunds rule. An atom is most stable if its outer shell is either fi lled or contains eight electrons, and if it has no electrons of higher energy. The octet rule states that an atom will give up, accept, or share electrons in order to fi ll its outer shell or attain an outer shell with eight electrons. Electronegative elements readily acquire electrons. The electronic confi guration of an atom describes the atomic orbitals occupied by the atoms electrons. A proton is a positively charged hydrogen ion; a hydride ion is a negatively charged hydrogen ion. Attractive forces between opposite charges are called electrostatic attractions. An ionic bond results from the electrostatic attraction between ions with opposite charges. Organic compounds are compounds that contain carbon. The atomic number of an atom is the number of protons in its nucleus (or the number of electrons that surrounds the neutral atom). The mass number of an atom is the sum of its protons and neutrons. Isotopes have the same atomic number, but different mass numbers. Atomic weight is the average mass of the atoms in the element. Molecular weight is the sum of the atomic weights of all the atoms in the molecule. An atomic orbital tells us the volume of space around the nucleus where an electron is most likely to be found. The closer the atomic orbital is to the nucleus, the lower is its energy. Minimum energy corresponds to maximum stability . Degenerate orbitals have the same energy. SOME IMPORTANT THINGS TO REMEMBER c. CH 2 Cl 2 e. H2CCH2 g. BeCl 2 b. H2CO d. NH 3 f. H2CCHBr h. BF 3