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Q59
(NDA-II/2024)
Science & Technology › Basic Science (Physics, Chemistry, Biology)
Official Key
Which of the following anions has a valency of -3 ?
Explanation
Valency is the combining capacity of an atom or ion, determined by the number of electrons it must gain, lose, or share to achieve a stable electronic configuration (octet). Anions are negatively charged ions formed when an atom gains electrons.
- Nitride (N3-): Nitrogen has an atomic number of 7, with 5 electrons in its valence shell. To achieve stability, it gains 3 electrons, resulting in a valency of -3.
- Nitrate (NO3-): This is a polyatomic ion consisting of nitrogen and oxygen with a net charge and valency of -1.
- Sulphide (S2-): Sulphur (atomic number 16) has 6 valence electrons. It gains 2 electrons to complete its octet, giving it a valency of -2.
- Sulphate (SO42-): This is a polyatomic ion with a net charge and valency of -2.
Thus, Nitride is the correct anion with a valency of -3.
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