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Questions and Answers
Which of the following orbital diagrams are incorrect?
A sodium atom has an electron configuration of 1s22s22p63s1. If the sodium atom becomes charged, its new electron configuration will be the same as which element?
neon
Which element has an atom in the ground state with a total of 3 valence electrons?
aluminum
How many electrons are in the outermost energy shell of a calcium atom?
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Which element has the electron configuration 1s22s22p3?
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What is the correct electron configuration for the element of silicon?
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Which of the following is the same for both hydrogen and potassium?
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What is the electron configuration of scandium (Sc) in Sc(NO3)3?
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Which atom in the ground state has the same electron configuration as a calcium ion, Ca2+, in the ground state?
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Which of the following is most likely the electronegativity value for chlorine?
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According to the periodic table, Mg will most likely react with elements in which of these groups?
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Which symbol represents an atom in the ground state with the most stable valence electron configuration?
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According to the electron-cloud model of the atom, an orbital is a?
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Which of the following elements has the lowest ionization energy?
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How many grams of sodium chloride are required to prepare 500 mL of a 0.199 M solution?
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A 0.67 L solution of ammonium sulfate, (NH4)2SO4, contains 0.81 mole of the solute. What is the approximate molarity of the solution?
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If 250 mL of a 0.96 M solution of acetic acid (C2H4O2) is diluted to 800 mL, what will be the approximate molarity of the final solution?
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Which of the following solutions will have the greatest concentration?
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When 80 g of sodium hydroxide, NaOH, are dissolved in enough water to make 500 mL of solution, what is the molarity of the solution?
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What is the molarity of a solution that contains 40 grams of NaOH in 0.50 liter of solution?
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Based on the above graph, what change will cause the solubility of KNO3 (s) to increase?
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Look at the scale above. Which of the following colors would pH paper most likely turn when dipped in a very acidic sample?
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A 1.0 M aqueous solution of which substance would have the lowest pH?
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What is the pH of a 0.001 M HNO3 solution?
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Mr. Smith lists five household items and asks his students to classify them into acidic, basic, and neutral substances. The table below shows the classification of the items made by four of his students. Who classified the items correctly?
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Using the table above, what is the correct formula for ammonium phosphate?
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The correct name for P2O5 is?
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The formula for dinitrogen tetroxide is?
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Which of the following is the name of the molecule PCl3?
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The correct formula of an ionic compound containing Al3+ and CO3 2- is?
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The empirical formula for C6H12 is?
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What shape does the molecule BF3 have?
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The empirical formula for a substance is CH2. If the molecular mass of the substance is 56, the molecular formula is?
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The compound contains 24.27% carbon (C), 4.07% hydrogen (H), and 71.65% chlorine (Cl) by mass. What is the empirical formula of the compound?
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The Lewis dot structure of methane (CH4) is shown below. What shape does it represent?
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Sulfur is represented by the following Lewis dot structure. What does it contain?
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A compound whose empirical formula is NO2 could have a molecular mass of?
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A compound contains 45.7% nitrogen and 53.3% oxygen by mass. What is the empirical formula of the compound?
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20 3(g) --> 3 ____ (g) which completes the chemical equation equation above?
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If 6 liters of hydrogen gas are used, how many liters of nitrogen gas will be needed for the above at STP?
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How many moles of copper are equivalent to 3.44 x 10^23 atoms of copper?
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The equation shows the combination of butane (C4H10). How many moles of water can be produced by 12.5 moles of C4H10 with excess oxygen?
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What mass of nitrogen is required to react with 16 grams of oxygen?
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Phosphoric acid, H3PO4, is neutralized by magnesium hydroxide, Mg(OH)2. How many moles of water will be produced from the neutralization of 0.24 mole of H3PO4?
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The reaction for the decomposition of ammonia (NH3) can be written as shown. If a student has 2.17 g of NH3, how many grams of hydrogen gas (H2) will be produced by the reaction?
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The number of molecules in 48 grams of oxygen gas (O2) is?
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If 1.0 mole of methane reacts with oxygen to produce carbon dioxide and water, what mass of water is produced?
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What volume will 35.9 g of hydrogen gas (H2) occupy at STP?
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How many moles of carbon dioxide (CO2) are produced when reacting 6.00 moles of butane (C4H10) in excess oxygen (O2)?
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What volume will 35.9 g of hydrogen gas (H2) occupy at STP?
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Study Notes
Orbital Diagrams and Electron Configurations
- Orbital diagrams indicate the distribution of electrons in atoms; some diagrams may be incorrect.
- Sodium's electron configuration is 1s² 2s² 2p⁶ 3s¹; when it becomes Na⁺, it resembles neon's configuration.
- Aluminum holds three valence electrons in its ground state.
- Calcium has two electrons in its outermost energy shell.
- Nitrogen's electron configuration is 1s² 2s² 2p³.
Electron Configurations and Ionic States
- Silicon has the correct electron configuration of 1s² 2s² 2p⁶ 3s² 3p².
- Calcium ion, Ca²⁺, shares its electron configuration with potassium, K.
- Cl is likely to have an electronegativity value around 3.0.
Reactivity and Chemical Properties
- Magnesium (Mg) typically reacts with elements in group 17 (halogens).
- Ne represents the most stable valence electron configuration in the ground state.
- According to the electron-cloud model, optimal electron positions are found in orbitals.
Molarity, Solutions, and Acids
- Molarity calculation: 500 mL of 0.199 M NaCl requires 2.93 grams of solute.
- Ammonium sulfate solution (0.67 L, 0.81 moles) has a molarity of approximately 1.2 M.
- Dilution of 250 mL of 0.96 M acetic acid to 800 mL results in a final molarity of 0.30 M.
Concentration Comparisons
- Concentration is highest when 2 moles of solute are dissolved in 1 liter of solution.
- Dissolving 80 grams of NaOH in 500 mL produces a 4 M solution.
- 40 grams of NaOH in 0.50 L gives a molarity of 2.0 M.
pH and Acidity
- Increasing temperature raises the solubility of KNO₃(s).
- pH paper dipped in a very acidic sample turns orange, indicating low pH.
- A 1.0 M solution of hydrohalic acid (Hal) has the lowest pH among common solutions.
- The pH of a 0.001 M HNO₃ solution is approximately 3.
Naming and Formulas
- Ammonium phosphate is represented as (NH₄)₃PO₄.
- P₂O₅ is known as diphosphorus pentoxide.
- Dinitrogen tetroxide is represented by the formula N₂O₄.
- Phosphorus trichloride corresponds to PCl₃.
Empirical and Molecular Formulas
- Empirical formula for C₆H₁₂ is simplified to CH₂.
- BF₃ has a trigonal planar molecular shape.
- If empirical formula is CH₂ and molecular mass is 56, the molecular formula is C₄H₈.
Chemical Reactions and Stoichiometry
- A compound with 24.27% C, 4.07% H, and 71.65% Cl by mass has the empirical formula CH₂Cl.
- Lewis structures depict methane (CH₄) as tetrahedral.
- If a given equation has 3g of reactant producing O₂, 3 moles yield 62.5 moles of water.
- The reaction of nitrogen with oxygen requires 5.6g N for 16g O₂.
Moles and Mass Calculations
- 0.24 mole of phosphoric acid yields 0.72 moles of water upon neutralization with Mg(OH)₂.
- 2.17 grams of NH₃ yield approximately 3.85 grams of hydrogen gas after decomposing.
- 48 grams of O₂ corresponds to about 9.03 × 10²³ molecules.
- Reacting 1 mole of methane to produce water yields 36 grams of H₂O.
- 35.9 grams of H₂ gas at STP occupies 399 liters of space.
Gaseous Law and Stoichiometry
- Producing carbon dioxide when reacting 6.00 moles of butane in excess O₂ will yield 24.0 moles of CO₂.
Studying That Suits You
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Description
Test your knowledge with these chemistry flashcards focused on orbital diagrams, electron configurations, and valence electrons. Each card presents a question that will challenge your understanding of atomic structure and electron arrangement. Ideal for chemistry students looking to reinforce their learning.
