객관식
How many protons and electrons are present in a neutral atom of strontium (Sr)?
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- 1. Intro to General Chemistry3h 46m
- Classification of Matter18m
- Physical & Chemical Changes19m
- Chemical Properties7m
- Physical Properties5m
- Intensive vs. Extensive Properties13m
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- Scientific Notation13m
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- 2. Atoms & Elements4h 17m
- The Atom9m
- Subatomic Particles15m
- Isotopes17m
- Ions27m
- Atomic Mass28m
- Periodic Table: Classifications11m
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- 10. Periodic Properties of the Elements3h 10m
- The Electron Configuration22m
- The Electron Configuration: Condensed4m
- The Electron Configurations: Exceptions13m
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- Paramagnetism and Diamagnetism8m
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- Valence Electrons of Elements12m
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- 11. Bonding & Molecular Structure3h 29m
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- 12. Molecular Shapes & Valence Bond Theory1h 58m
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- Molecular Polarity10m
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- 15. Chemical Kinetics2h 53m
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- 17. Acid and Base Equilibrium5h 5m
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- Amphoteric Species5m
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- 18. Aqueous Equilibrium4h 47m
- Intro to Buffers20m
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- Solubility Product Constant: Ksp17m
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- Intro to Radioactivity10m
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- 22. Organic Chemistry5h 7m
- Introduction to Organic Chemistry8m
- Structural Formula8m
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- Skeletal Formula6m
- Spatial Orientation of Bonds3m
- Intro to Hydrocarbons16m
- Isomers11m
- Chirality15m
- Functional Groups in Chemistry11m
- Naming Alkanes4m
- The Alkyl Groups9m
- Naming Alkanes with Substituents13m
- Naming Cyclic Alkanes6m
- Naming Other Substituents8m
- Naming Alcohols11m
- Naming Alkenes11m
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- Naming Ketones5m
- Naming Aldehydes5m
- Naming Carboxylic Acids4m
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- Naming Ethers5m
- Naming Amines5m
- Naming Benzene7m
- Alkane Reactions7m
- Intro to Addition Reactions4m
- Halogenation Reactions4m
- Hydrogenation Reactions3m
- Hydrohalogenation Reactions7m
- Alcohol Reactions: Substitution Reactions4m
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- Intro to Redox Reactions8m
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- Aldehydes and Ketones Reactions6m
- Ester Reactions: Esterification4m
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- Amine Reactions3m
- Amide Formation4m
- Benzene Reactions10m
- 23. Chemistry of the Nonmetals2h 39m
- Main Group Elements: Bonding Types4m
- Main Group Elements: Boiling & Melting Points7m
- Main Group Elements: Density11m
- Main Group Elements: Periodic Trends7m
- The Electron Configuration Review16m
- Periodic Table Charges Review20m
- Hydrogen Isotopes4m
- Hydrogen Compounds11m
- Production of Hydrogen8m
- Group 1A and 2A Reactions7m
- Boron Family Reactions7m
- Boron Family: Borane7m
- Borane Reactions7m
- Nitrogen Family Reactions12m
- Oxides, Peroxides, and Superoxides12m
- Oxide Reactions4m
- Peroxide and Superoxide Reactions6m
- Noble Gas Compounds3m
- 24. Transition Metals and Coordination Compounds3h 19m
- Atomic Radius & Density of Transition Metals11m
- Electron Configurations of Transition Metals7m
- Electron Configurations of Transition Metals: Exceptions11m
- Paramagnetism and Diamagnetism10m
- Ligands10m
- Complex Ions5m
- Coordination Complexes7m
- Classification of Ligands11m
- Coordination Numbers & Geometry9m
- Naming Coordination Compounds22m
- Writing Formulas of Coordination Compounds8m
- Isomerism in Coordination Complexes17m
- Orientations of D Orbitals4m
- Intro to Crystal Field Theory10m
- Crystal Field Theory: Octahedral Complexes5m
- Crystal Field Theory: Tetrahedral Complexes4m
- Crystal Field Theory: Square Planar Complexes4m
- Crystal Field Theory Summary8m
- Magnetic Properties of Complex Ions9m
- Strong-Field vs Weak-Field Ligands6m
- Magnetic Properties of Complex Ions: Octahedral Complexes11m
2. Atoms & Elements
The Atom
Multiple Choice
An atom has an atomic number of 15 and a mass number of 31. How many protons are present in this atom?
A
16
B
46
C
15
D
31
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검증된 단계별 안내1
Recall that the atomic number of an atom represents the number of protons in its nucleus.
Identify the atomic number given in the problem, which is 15.
Understand that the mass number is the sum of protons and neutrons, but it does not affect the number of protons directly.
Since the atomic number is 15, the atom has 15 protons.
Therefore, the number of protons in the atom is equal to the atomic number, which is 15.
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