In the modern periodic table, period indicates the value of
Correct answer: C. Principal quantum number
- A. Atomic number
- B. Atomic mass
- C. Principal quantum number
- D. Azimuthal quantum number
Explanation
The correct answer is the Principal quantum number. In the modern periodic table, the period number of an element corresponds to the principal quantum number, which indicates the main energy level occupied by the electrons. Each period in the periodic table represents a new principal energy level.Option A, Atomic number, is incorrect because the atomic number is the number of protons in an element's nucleus and determines its identity but not its period.Option B, Atomic mass, is incorrect because it reflects the mass of an atom, not its position in a period.Option D, Azimuthal quantum number, is incorrect because it describes the shape of the orbital, not the energy level represented by the period.
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About Periodic Properties and Trends
Periodic properties arise from electron configuration and effective nuclear charge, producing trends in atomic and ionic radius, ionization energy, electron affinity, electronegativity, metallic character and reactivity. Comparisons run across periods and down groups, with attention to common exceptions. The topic also relates these trends to the behavior of s-block and p-block elements.
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