In which groups of the periodic table are transition elements located?
Groups 3 to 12.
What is a characteristic feature of transition elements in terms of their oxidation states?
They have variable oxidation states.
Why do transition metals exhibit variable oxidation states?
Due to the availability of both ns and (n-1)d electrons for bonding.
What property of transition metal ions is responsible for their colour?
The presence of partially filled d orbitals.
What type of ions do transition metals form?
Coloured ions.
What are complex ions?
Ions formed when a transition metal is surrounded by ligands.
Are transition metals good conductors of heat and electricity?
Yes, they are good conductors.
Do transition metals have high or low melting points?
They have high melting points.
What is the use of iron in the Haber process?
It is used as a catalyst.
Which transition metal is used in the Ostwald process?
Platinum.
What is the use of vanadium(V) oxide?
It is a catalyst in the contact process.
What transition metal is used in the production of margarine?
Nickel.
What are some common uses of transition elements?
Catalysts, pigments, alloys, and electrodes.
Give an example of a coloured ion formed by a transition metal.
Copper(II) ions are blue.
Are transition elements hard or soft materials?
They are hard materials.
What type of bonding is present in transition metals?
Strong metallic bonding.
What is the oxidation state of iron in iron(III) chloride?
+3
What is the name given to the species that surrounds the metal ion in a complex?
Ligand.
Do transition elements form paramagnetic or diamagnetic substances?
They tend to form paramagnetic substances.
Are transition metals very reactive?
They are generally less reactive than group 1 and 2 metals.
Explanation Questions
Explain why transition elements have variable oxidation states.
Transition elements have variable oxidation states because they can use both their ns and (n-1)d electrons for bonding. The energy levels of these electrons are very close, allowing them to be lost in different combinations. This leads to multiple stable oxidation states for a single transition element.
Explain why transition metal ions are often coloured.
The colour of transition metal ions is due to the presence of partially filled d orbitals. When white light shines on transition metal ions or complexes, electrons in the d orbitals can absorb specific wavelengths of light and move to a higher energy level. The remaining unabsorbed wavelengths of light are transmitted, and give the ion a specific colour.
Explain why transition metals have high melting and boiling points.
Transition metals have high melting and boiling points because of the strong metallic bonds between their atoms. These bonds are formed due to the delocalized electrons that are shared among the atoms. The involvement of both ns and (n-1)d electrons in metallic bonding makes these bonds particularly strong, requiring more energy to break, resulting in high melting and boiling points.
Explain how transition elements form complexes.
Transition metals form complexes due to their ability to accept electron pairs from ligands. Ligands are molecules or ions that have lone pairs of electrons and they bond to the metal ion through coordinate bonds. Transition metal ions have vacant d orbitals that can accept these electron pairs, forming coordinate bonds and stable complexes.
Describe the role of iron in the Haber process and explain why it is effective.
In the Haber process, iron acts as a catalyst, providing a surface on which nitrogen and hydrogen molecules can adsorb and react to form ammonia. The iron catalyst reduces the activation energy of the reaction, increasing the rate of reaction without being consumed. Iron is effective because it provides active sites on its surface for the reactants to bond to, which weakens their own bonds and allows the reaction to occur more quickly.
Explain why transition elements are good conductors of heat and electricity.
Transition metals are good conductors of heat and electricity due to the delocalised nature of their outer s and d electrons. These electrons are free to move throughout the metal structure, enabling the transfer of kinetic energy (heat) or electric charge (electricity) from one atom to another, which makes them good conductors.
What are the main physical properties of transition elements, and why are they useful?
Transition elements are typically hard, dense materials with high melting and boiling points and are good conductors of heat and electricity. These properties make them useful for applications such as making strong alloys for construction, conducting wiring, and heating elements. Their catalytic activities also make them useful in many industrial processes.
Describe the trend in atomic radius across the transition elements.
The atomic radius of transition elements tends to decrease across the period until it gets to around group 8, then it becomes constant across the rest of the d-block. This is due to increasing nuclear charge as more electrons are added to the 3d orbitals. The increase in electrons leads to shielding, which balances out the increased nuclear charge at around group 8, hence the atomic radii become constant.
Explain why most transition metal compounds are paramagnetic.
Transition metal compounds are paramagnetic because they have unpaired electrons in their d orbitals. Paramagnetism is the tendency of a substance to be attracted into a magnetic field. When a compound has unpaired electrons, they create their own magnetic field. These fields then interact with an external magnetic field.
Explain why the transition elements are generally less reactive than group 1 and 2 metals.
Transition metals are generally less reactive than Group 1 and 2 metals because of the stronger electrostatic forces between the ns and (n-1)d electrons and the nucleus, due to increased nuclear charge. This increases the ionisation energy, and the energy required to remove these electrons is higher, making them less likely to react.