Which of the following is not an actinide?
Curium
Californium
Erbium
Americium
Related Questions
Which of these is an INCORRECT observation about alkali metals?
Are generally soft.
Have shiny surfaces when freshly cut.
Exhibit characteristic flame colors.
Produce a violet flame when heated.
Which actinide element is primarily used as fuel in nuclear reactors?
Thorium
Uranium
Plutonium
Americium
Actinides exhibit greater variability in oxidation states than lanthanides. This is primarily due to:
The greater shielding effect of 5f electrons.
The comparable energies of 5f, 6d, and 7s orbitals.
The smaller size of actinide atoms.
The lower reactivity of actinides.
The third ionization enthalpy of Gadolinium is relatively low. This is primarily attributed to the:
Stability of the half-filled 4f subshell
Stability of the fully-filled 4f subshell
Small size of the ion
High electronegativity of Gadolinium
Gadolinium (Gd, Z=64) is used in MRI contrast agents. Explain why its 4f electrons do not significantly participate in chemical bonding.
High ionization energy of 4f electrons
Low electronegativity of gadolinium
Shielding by 5s and 5p orbitals
Relativistic effects on 4f orbitals
Which element is NOT a lanthanide?
Cerium (Ce)
Promethium (Pm)
Actinium (Ac)
Europium (Eu)
Which element has the electronic configuration ?
Eu
Gd
Tb
Dy
Actinides
Have variable valency
Include element 12
Are all synthetic elements
Have only short lived isotopes
Which of the following is the correct electronic configuration of Gadolinium (Gd, Atomic No. 64)?
[Xe] 4f8 6s2
[Xe] 4f7 5d1 6s2
[Xe] 4f7 6s2
[Xe] 4f6 5d2 6s2
Lanthanides are known for their characteristic +3 oxidation state. Which of the following statements contradicts this established behavior?
They readily form +3 ions.
They exhibit variable oxidation states, though +3 is most common.
They readily form -3 ions.
Their +3 ions often exhibit color due to f-f transitions.
