An electrovalent bond, also known as an ionic bond, is formed by the complete transfer of one or more electrons from one atom to another. This typically occurs between a metal (electropositive element) and a non-metal (electronegative element).

Why (A) is correct:

Option (A) correctly describes the formation of an electrovalent bond. Electropositive elements (metals) tend to lose electrons to achieve a stable electron configuration, forming positive ions (cations). Electronegative elements (non-metals) tend to gain electrons to achieve a stable electron configuration, forming negative ions (anions). The electrostatic attraction between these oppositely charged ions constitutes the ionic bond.

Option Analysis:

• (A) transfer of electrons from electropositive to electronegative element. This is the correct definition of an electrovalent (ionic) bond.
• (B) sharing of electrons between the atoms. This describes the formation of a covalent bond, not an electrovalent bond.
• (C) donation of electrons. While electrons are donated by one atom, the term 'donation' alone doesn't fully capture the 'transfer' to another specific type of element (electronegative) which is crucial for ionic bond formation. It's a partial description.
• (D) transfer of electrons from electronegative to electropositive element. This is incorrect. Electronegative elements tend to gain electrons, not lose them to electropositive elements.

Correct Answer: (A)