Transition metals in the periodic table show several typical properties. Which of the following is NOT a characteristic property of transition metals?

Introduction / Context:

Transition metals are the d block elements of the periodic table and are widely known for their rich chemistry. They form coloured compounds, show variable oxidation states, and often act as catalysts. Questions in general science and chemistry examinations frequently ask about these characteristic properties and also about features that are not typical of transition metals. This question requires the learner to select which given property does not match the usual behaviour of transition metals.

Given Data / Assumptions:

• The focus is on transition metals, which occupy the central block of the periodic table.
• Options include properties such as forming coloured ions, gaining electrons, variable oxidation states, catalytic activity, and complex formation.
• Only one option should describe a behaviour that is not characteristic for metals of this group.
• We assume school level understanding of metallic character and electron transfer.

Concept / Approach:

Transition metals are metals and therefore tend to lose electrons to form positive ions (cations) rather than gain electrons. They often show multiple oxidation states because they can lose different numbers of d and s electrons. Many transition metal compounds are coloured due to d d electronic transitions. They also readily form complex ions with ligands such as water, ammonia, and cyanide, and they act as catalysts in numerous industrial and biological reactions. The tendency to gain electrons and form negative ions is more typical of nonmetals such as halogens. Therefore, the statement that transition metals tend to gain electrons and form negative ions is not a correct characteristic of this group.

Step-by-Step Solution:

Step 1: Recall that transition metals are metallic elements and share general metallic properties such as forming positive ions. Step 2: Identify known characteristic properties of transition metals: coloured compounds, variable oxidation states, complex formation, and catalytic behaviour. Step 3: Compare each option with this list, noting that most match these known characteristics. Step 4: Recognise that gaining electrons and forming negative ions is a property of nonmetals, not of metals. Step 5: Select tendency to gain electrons and form negative ions as the option that is not a characteristic of transition metals.

Verification / Alternative check:

Chemistry textbooks describe transition metals as elements with partially filled d subshells that form cations by losing electrons. They give many examples, such as Fe forming Fe2 plus and Fe3 plus, and Cu forming Cu plus and Cu2 plus. These texts highlight the variable oxidation states and the colourful nature of their salts, as well as their roles as catalysts, for example in the Haber process and catalytic converters. They do not list formation of negative ions as a property of transition metals. This supports the idea that gaining electrons is not typical behaviour for this group.

Why Other Options Are Wrong:

Option A, Tendency to form coloured ions, is correct for many transition metals, whose solutions and crystals show vivid colours. Option C, Variable oxidation states, is another hallmark of transition metals, arising from the participation of both s and d electrons in bonding. Option D, Ability to act as catalysts, is a common feature, with metals like Fe, Ni, and Pt widely used in industrial catalysis. Option E, Formation of complex ions with ligands, is also characteristic of transition metals, which often form stable complexes with water, ammonia, and other ligands.

Common Pitfalls:

Students may rush through the question and choose a property that seems unusual, such as coloured ions or complex formation, without remembering that these are actually classic features of transition metals. Others may think that both losing and gaining electrons are possible behaviours and fail to consider that metals mainly lose electrons. To avoid such errors, learners should remember the basic rule that metals, including transition metals, tend to form positive ions, whereas nonmetals like halogens tend to gain electrons to form negative ions.

Final Answer:

The property that is not characteristic of transition metals is a tendency to gain electrons and form negative ions.