Question

The central atom/ions in coordination compounds are referred to as:

• A. Lewis base
• B. Lewis acid
• C. Bronsted acid
• D. Bronsted base

Answer 1

The Correct Option is B

The central atom/ion in coordination compounds is referred to as a Lewis acid.

To understand why this is the correct term, we need to explore some chemical concepts:

1. Lewis Acid: A Lewis acid is defined as a chemical species that can accept an electron pair. In coordination chemistry, the central atom or ion acts as a Lewis acid because it can accept electron pairs from ligands, which are Lewis bases that donate electron pairs.
2. Coordination Compounds: These compounds consist of a central atom/ion surrounded by molecules or ions called ligands. The central metal ion attracts these ligands to form a stable structure due to its ability to accept electron pairs.
3. Example: In a coordination compound like [Cu(NH₃)₄]²⁺, copper (Cu) is the central ion, and it acts as a Lewis acid by accepting electron pairs from ammonia (NH₃) molecules.

Therefore, the central atom/ions in coordination compounds are best described as Lewis acids.

Answer 2

In coordination chemistry, the central atom or ion in a coordination compound is typically a metal ion (often a transition metal) that can accept electron pairs. This makes it a Lewis acid.

• A Lewis acid is defined as a substance that can accept an electron pair.
• The ligands (the molecules or ions that surround the central atom) act as Lewis bases because they donate electron pairs to the metal ion (the Lewis acid).
• The metal ion at the center of a coordination compound typically has vacant orbitals, allowing it to accept electron pairs from the ligands.

Therefore, it acts as an electron-pair acceptor, classifying it as a Lewis acid.

Thus, the correct answer is Option B: Lewis acid.