January 2008 Chemistry Regents #1-10
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Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50 |
Questions | Answer | Explanations |
| 1 Which quantity identifies an element? (1) atomic number (2) mass number (3) total number of neutrons in an atom of the element (4) total number of valence electrons in an atom of the element | 1 | atomic number is the number of protons |
| 2 Which atom in the ground state has a partially filled second electron shell? (1) hydrogen atom (3) potassium atom (2) lithium atom (4) sodium atom | 2 | Li 2-1 |
| 3 What is the total charge of the nucleus of a nitrogen atom? (1) +5 (3) +7 (2) +2 (4) +14 | 3 | 7 protons |
| 4 Which value of an element is calculated using both the mass and the relative abundance of each of the naturally occurring isotopes of this element? (1) atomic number (3) half-life (2) atomic mass (4) molar volume | 2 | definition of atomic mass |
| 5 The mass of 12 protons is approximately equal to (1) 1 atomic mass unit (2) 12 atomic mass units (3) the mass of 1 electron (4) the mass of 12 electrons | 2 | each proton is 1 amu |
| 6 Sodium atoms, potassium atoms, and cesium atoms have the same (1) atomic radius (2) first ionization energy (3) total number of protons (4) oxidation state | 4 | +1, group 1s |
| 7 Which statement describes a chemical property of hydrogen gas? (1) Hydrogen gas burns in air. (2) Hydrogen gas is colorless. (3) Hydrogen gas has a density of 0.000 09 g/cm3 at STP. (4) Hydrogen gas has a boiling point of 20. K at standard pressure. | 1 | chemical properties involve reactions |
| 8 Which element has the greatest density at STP? (1) calcium (3) chlorine (2) carbon (4) copper | 4 | Table S |
| 9 Which equation shows conservation of atoms? (1) H2 + O2 ==> H2O (2) H2 + O2 ==>2H2O (3) 2H2 + O2 ==> 2H2O (4) 2H2 + 2O2 ==> 2H2O | 3 | atoms in equal atoms out |
| 10 Which term indicates how strongly an atom attracts the electrons in a chemical bond? (1) alkalinity (2) atomic mass (3) electronegativity (4) activation energy | 3 | definition of electronegativity Table S |