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Q13
(NDA-II/2016)
Science & Technology › Basic Science (Physics, Chemistry, Biology) › Periodic table elements
Answer Verified
Identify Ihe element having zero valency
Result
Your answer:
—
·
Correct:
D
Explanation
Valency is defined as the combining capacity of an atom, which is determined by the number of electrons in its outermost shell [2]. Noble gases possess a completely filled valence shell, making them chemically inert and giving them a valency of zero [1]. Radon (Rn) is a noble gas located in Group 18 of the periodic table. Because its outermost energy level is full with eight electrons, it has no tendency to gain, lose, or share electrons under standard conditions, resulting in zero valency [1]. In contrast, Sulphur typically has valencies of 2, 4, or 6, Phosphorus has valencies of 3 or 5 [3], and Lead (Pb) commonly exhibits valencies of 2 or 4. Therefore, among the given options, Radon is the only element with zero valency.
Sources
- [1] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > 3.3 HOW DO METALS AND NON-METALS REA ALS REACT? > p. 46
- [2] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > 4.2.3 Will you be my Friend? > p. 66
- [3] http://www.macw.ac.in/downloads/files/n5e8d635b86a61.pdf
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