August 2015 Chemistry Regents #36-40
Highlight to reveal answers and explanations
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Questions | Answer | Links | Explanations |
36 As the first five elements in Group 15 are considered in order of increasing atomic number, first ionization energy (1) decreases (2) increases (3) decreases, then increases (4) increases, then decreases | 1 | link | Use Table S |
1 | link | hydrogen bonding look for H with F, O or N | |
38 Which ion in the ground state has the same electron configuration as an atom of argon in the ground state? (1) A13+ (3) K+ (2) O2- (4) F- | 3 | link | argon has 18 electrons K+ has 18 electrons 19 lose 1=18 |
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39 What is the number of pairs of electrons shared in a molecule of N2? (1) 1 (3) 3 (2) 2 (4) 6 | 3 | link | triple bond has 6 electrons or 3 pairs of electrons |
40 Which statement explains why a C–O bond is more polar than a F–O bond? (1) At STP, carbon has a greater density than fluorine. (2) A carbon atom has more valence electrons than a fluorine atom. (3) The difference in electronegativity between carbon and oxygen is greater than that between fluorine and oxygen. (4) The difference in first ionization energy between carbon and oxygen is greater than that between fluorine and oxygen. | 3 | link | BEND- Bonding electronegativity difference Large difference is more polar |
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