Question

14. When are atoms most stable? A) when they have the fewest possible yale (B) when they have the ma C) when all of the electron Orbit D) when all electrons are paired e the fewest possible valence electrons they have the maximum number of unpaired electrons in all of the electron orbitals in the valence shell are filled ods with 15. Water molecules can form hydrogen bonds with Acompounds that have polar covalent bonds B) compounds that have non-polar covalent bonds C) oxygen gas (O2) molecules D) chloride ions 16. Which type of bond must be broken for water to vaporize? A) ionic bonds B) polar covalent bonds @hydrogen bonds D) both polar covalent bonds and hydrogen bonds 17. Hydrophobic substances such as vegetable oil are A) nonpolar substances that repel water molecules B) nonpolar substances that have an attraction for water molecules C) polar substances that repel water molecules D) polar substances that have an affinity for water 18. Which of the following solutions would require the addition of the greatest amount of base to bring the solution to neutral pH? gastric juice at pH 2 B) vinegar at pH 3 C) black coffee at pH 5 D) household bleach at pH 12 19. Which of the following statements is true about buffer solutions? A) They maintain a constant pH when bases are added to them but not when acids are added to them. B) They maintain a constant pH when acids are added to them but not when bases are added to them. C) They fluctuate in pH when either acids or bases are added to them. D) They maintain a relatively constant pH when either acids or bases are added to them. 20. The element(s) present in all organic molecules is_ A) hydrogen B) oxygen and carbon carbon and hydrogen D) nitrogen

Answer 1

14.) D. When all electrons are paired.

Because half filled and completely filled orbitals are more stable in comparison to incompletely filled orbitals. Among them completely filled orbitals are more stable because they don't have any valence electrons for sharing with any other atoms. For example: He, Ne, Ar etc. are maximum stable as they are not a reacting species because of completely filled orbitals.