Which of the following elements belongs to Group 2, Period 3?
A. Mg
B. Sr
C. Be
D. Ca
Answer: Option A
Solution (By JKExamLibrary)
Magnesium (Z=12): configuration 2,8,2. Period = number of shells = 3; Group = 2 (2 valence electrons). Be is Group 2, Period 2; Ca is Group 2, Period 4; Sr Period 5.
Explanation:
Rhizobium is a nitrogen-fixing bacterium that lives in root nodules of legumes and converts atmospheric N₂ to ammonia, enriching soil fertility naturally. It is a biofertilizer. Urea and ammonium sulfate are synthetic nitrogenous fertilizers. Superphosphate is a synthetic phosphorus fertilizer. Biofertilizers like Azotobacter, Blue-green algae, and mycorrhizae are eco-friendly and sustainable.
Explanation:
Oxidation is defined as the loss of electrons (or an increase in oxidation state). A reducing agent is a substance that donates electrons to another species, thereby causing the other species to be reduced. In doing so, the reducing agent itself gets oxidized. Thus, statement 1 is correct, but 2 is incorrect.
Explanation:
Reverse osmosis uses a semipermeable membrane to reject dissolved salts and impurities. Filtration removes solids; chlorination/ozonation disinfect but do not remove salts.
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