June 2010 Chemistry Regents #51-53

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Questions

Base your answers to questions 51 to 53 on the information below.

51 What is the total number of electron pairs shared between the carbon atom and one of the oxygen atoms in a carbon dioxide molecule? [1]

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Answer =2 pairs

O=C=O

(4 electrons but the question wanted "pairs")

52 Explain, in terms of subatomic particles, why the radius of a chloride ion is larger than the radius of a chlorine atom. [1]

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NOTE= Subatomic particles are protons neutrons and electrons (use it)

A Cl ion has 18 electrons and 17 protons, so there is less attraction by the nucleus for the electron shells, allowing the electron shells to expand.

The radius of Clis larger because the nucleus canít hold 18 electrons as close as it can hold 17 electrons.

The ratio of electrons to protons is greater in the ion than the atom, so the ion is larger.

53 Explain, in terms of valence electrons, why the bonding in magnesium oxide, MgO, is similar to the bonding in barium chloride, BaCl2. [1]

 

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WRONG ANSWER=Ionic  (in terms of valence electrons)

The bonding in each compound involves a transfer of valence electrons from the metal to the nonmetal.

Both metals lose all of their valence electrons.

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Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50

 Questions 51-53 Questions 54-55 Questions 56-58 Questions 59-61 Questions 62-64 Questions 65-68 Questions 69-71 Questions 72-75 Questions 76-79 Questions 80-83

 
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