1989 National Test1. Gallium reacts with element Y to form a compound with theformula GaY. If barium were to combine with element Y, the formula of the product would most likely be(A) BaY(B) Ba2Y(C) Ba2Y3(D) Ba3Y22. The number of significant figures one can assume in the atomic weight of 12C is3. A compound X2O3contains 31.58% oxygen by weight. The atomic weight of X is4. The emission spectrum of the hydrogen atom5. Cathode rays are(A) a beam of positively charged particles.(B) nuclei of helium atoms.(C) fast-moving neutrons.(D) streams of electrons.6. Which atom has the correct ground state electron configuration?7. The correct number of unpaired electrons in the ground state of a neutral cobalt atom is:8. Which electron configuration describes a neutral atom in an excited state?9. The first ionization potential for S is lower than the first ionization potential for P because(A) Hund's rule is violated.(B) ionization potentials decrease across a representative period.(C) half-filled and filled sets of orbitals are more stable than configurations of one more or fewer electrons.(D) The statement above is false. The first ionization potential for S is higher than that for P.10. Which set of quantum numbers describe the most easily-removed electron from a neutral iron atom?11. The molecular ion XF2¯ has three pairs of non bonding electrons around the central atom. The bond angle F-X-F will be closest to12. Which species has a pyramidal structure?13. Which molecule is polar?(A) CO2(B) SF6(C) BCl3(D) SF4
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