WBCS.LIVE practice question

0 is isoelectronic with

Solve this multiple-choice question and check the correct answer with its explanation below.

Answer options

  1. F⁻
  2. Cl⁻
  3. Li⁺
  4. K⁺

Correct answer and explanation

Correct answer: F⁻

Explanation: The oxide ion O²⁻ is isoelectronic with F⁻, as both have 10 electrons. 📚 Other Information: ▪️ 'Isoelectronic' means having the same number of electrons. ▪️ Oxygen (atomic number 8) gains two electrons → O²⁻ (10 electrons). ▪️ Fluorine (atomic number 9) gains one electron → F⁻ (10 electrons). ▪️ Hence, O²⁻ and F⁻ have the same electronic configuration: 1s² 2s² 2p⁶. ▪️ Isoelectronic species often show similar chemical behaviour. ▪️ Example: Na⁺, Mg²⁺, Ne, F⁻, and O²⁻ are all isoelectronic. ▪️ Such ions differ in nuclear charge but have the same electron number. ▪️ The greater the nuclear charge, the smaller the ionic radius.