d and f BLOCK ELEMENTS

How does the presence of unpaired d-electrons influence the melting points of transition metals?

• It leads to weaker metallic bonds and lower melting points
• It leads to stronger metallic bonds and consequently higher melting points
• It has no effect on melting points
• It makes the metals more volatile

What is the typical trend of third ionisation enthalpies in the 3d transition series?

• They decrease across the series
• They generally increase with atomic number, with a break at the element forming a d5 ion
• They remain constant across the series
• They show no discernible trend

Why do the atomic radii of transition elements decrease only slightly from left to right across a period?

• Electrons are added to the same shell
• Effective nuclear charge increases slowly due to shielding by (n-1)d electrons
• The nuclear charge remains constant
• Electrons occupy higher energy levels

What is the primary factor that determines the strength of metallic bonding in transition elements?

• The atomic mass
• The number of unpaired electrons available for delocalisation
• The nuclear charge
• The atomic radius

Why do transition metals typically form compounds with multiple oxidation states?

• They have low ionisation enthalpies
• Due to the small energy difference between the (n-1)d and ns orbitals
• They have high electronegativity
• They readily gain electrons