Actinoids Flashcards
Actinoids are
Ac , Th to Lr 14 elements
Earlier members have ____ half life
Later members have half life ranging from ____ to 3 min thus could be prepared in nanograms only
Longer
One day
Q: What is the general electronic configuration of actinoids?
A: The general electronic configuration of actinoids is 7 s² with variable occupancy of the 5 f and 6d subshells.
How many electrons are formally added to the subshell in actinoids?
A: Fourteen electrons are formally added to the subshell.
Q: At which element do the orbitals become complete in actinoids?
A: The orbitals become complete at element 103 (Lawrencium).
Q: From which element onwards do the orbitals begin filling in actinoids?
A: The orbitals begin filling from Protactinium (Pa, ) onwards.
Q: From which element onwards do the orbitals begin filling in actinoids?
A: The orbitals begin filling from Protactinium (Pa, ) onwards.
Q: What causes the irregularities in the electronic configurations of actinoids?
A: The irregularities are related to the stabilities of f⁰ f⁷ , and f¹⁴ occupancies of the 5f orbitals.
Q: What are the electronic configurations of Americium (Am) and Curium (Cm)?
A:
Americium (Am): Rn 5f⁷ 7s²
Curium (Cm):Rn 5f⁷ 6d¹ 7s²
Q: How do 5f orbitals differ from 4f orbitals but resembles in angular wave function ?
A: 5f orbitals are less buried than 4 f orbitals, allowing electrons to participate in bonding to a greater extent.
Q: How do 5f orbitals differ from 4f orbitals but resembles in angular wave function ?
A: 5f orbitals are less buried than 4 f orbitals, allowing electrons to participate in bonding to a greater extent.
what is actinoid contraction
gradual decrease in size of atoms or M3+ ions across the series
what causes actinoid contractions
poor shielding effect of 5f orbitals
How does the actinoid contraction compared to lanthanoid contractions
actinoid contraction is greater
what is the term used for gradual decrease in size of actinoids
actinoid contractions
Q: Why do actinoids exhibit a greater range of oxidation states?
A: Because the 5f, 6d, and 7s levels are of comparable energies.
Q: What is the general oxidation state of actinoids?
A: +3 oxidation state.
Q: How does the maximum oxidation state change in the first half of the actinoid series?
A: It increases from +4 in Th to +5, +6, and +7 in Pa, U, and Np, respectively, but decreases in the succeeding elements.
How do actinoids resemble lanthanoids in terms of oxidation states?
A: Both have more compounds in the +3 state than in the +4 state.
What happens to +3 and +4 ions of actinoids?
A: They tend to hydrolyze.
Why is it unsatisfactory to describe the chemistry of actinoids solely in terms of oxidation states?
A: Because the distribution of oxidation states is uneven and varies significantly between the early and later actinoid
: Why do +3 and +4 ions of actinoids tend to hydrolyze?
A: Due to their high charge-to-size ratio, which increases their reactivity with water.
Q: Why is it unsatisfactory to review actinoid chemistry in terms of oxidation states?
A
: The distribution of oxidation states is highly uneven: higher oxidation states are common in the early actinoids (e.g., Pa, U, and Np), while later actinoids predominantly show lower oxidation states (e.g., +3), leading to inconsistent behavior across the series.
Q: What is the general appearance of actinoid metals?
A: Actinoid metals are all silvery in appearance.