Question
Identify an element that does NOT belong to the third period.
The correct answer is
Bromine
Periodic Table: Element Identification for Third Period
The period number in the periodic table corresponds to the principal energy level (electron shell) of the valence electrons.
Third Period Elements:
- Sodium (Na)
- Magnesium (Mg)
- Aluminum (Al)
- Silicon (Si)
- Phosphorus (P)
- Sulfur (S)
- Chlorine (Cl)
- Argon (Ar)
Analysis of Options:
- Silicon (Si): Atomic number 14. Its electron configuration ends in the third principal energy level. It belongs to the 3rd period.
- Argon (Ar): Atomic number 18. It is the last element in the 3rd period.
- Bromine (Br): Atomic number 35. Its electron configuration indicates valence electrons in the fourth principal energy level. It belongs to the 4th period.
- Phosphorus (P): Atomic number 15. It belongs to the 3rd period.
Based on the analysis, Bromine is the element that does NOT belong to the third period.
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Important Questions from Periodic Classification
Element X forms a chloride with the formula XCl2, which is a solid with high melting point. X would most likely be in the same group of periodic table as
Element X forms a chloride with the formula XCl2, which is a solid with high melting point. X would most likely be in the same group of periodic table as
- Which of the following statements is NOT correct with reference to the p-block elements?
- Where did Mendeleev arrange the elements in the periodic table with similar properties?
- What was the unknown element under aluminium called?
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