Questions tagged [periodic-trends]
Trends which are observed in the properties of elements as you move along the periodic table in a given direction.
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How to compare the oxidizing power of perhalate ions
In my book the oxidizing power in descending order of the following is given as: $\ce{BrO4-} > \ce{IO4-} > \ce{ClO4-}$
My doubt is regarding their order of oxidizing tendency.
I thought that ...
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What determines the kind of Bravais lattice structure (body-centred cubic, hexagonal, etc) a transition metal shows?
With the exception of Zn, Hg, Cd and Mn transition metals most transition metals have only one kind of lattice structure at room temperature. Another trend I noticed was that Groups 3 and 4 have ...
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Relative orbital energies of Mn and Ni
In this MO diagram, why are the atomic Mn $3d$ orbitals higher in energy than the Ni $3d$ orbitals?
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Trends in Slater's constant
I am aware of the various Slater rules to calculate the effective nuclear charge, $Z_\mathrm{eff}$
However, how can I decide the order in which the orbitals 2s, 3s, 3d, 3p, 4d, and 4f stand when ...
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How to rationalise the trend in the covalent radii of the transition metals?
Why do the covalent radii of transition series decrease at the start rapidly, then become almost constant and at the end of series begin to increase from left to right in periodic table?
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Is there an enolate equivalent for enamines?
I'm learning that enolates are stronger than enamines are stronger than enols in terms of general nucleophilicity. Makes sense. But what I can't find any explanation for online is why the trend ...
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Comparing electronegativities of aluminium and gallium
If I were to compare the electronegativities of Al and Ga, shouldn't I be saying that the electronegativity of elements (in general) decreases down the group, I say this by thinking of the position of ...
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How to explain the periodic trends in boiling points in groups?
Observing the trend of boiling points of the compounds listed, choose the appropriate terms to fit into the blanks:
\begin{array}{lr}
\hline
\text{Compound} & \text{b.p.}/\pu{°C}\\
\hline
\ce{H2Te}...
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why lawrencium is placed in f-block elements although its last electron enters in 6d-subshell?
The electronic configuration of lawrencium ($\ce{Lr}$) is $\mathrm{[Rn] 7s^2 5f^{14} 6d^1}$. As its last electron enters the $\mathrm{6d}$ sub shell, it should be a part of $\mathrm{d}$-block elements,...
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Why does the electron affinity increase become more exothermic down group 2 and group 5?
It is generally true that the electron affinity becomes less exothermic down a group, because of the increase in atomic radius.
There is a well-known exception that the electron affinity of Cl is ...
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Why are the Covalent Radii of Ruthenium and Osmium So Similar?
Osmium and Ruthenium have covalent radii 144 and 146 respectively (according to Wikipedia).
How are these values so similar when Osmium has 32 more electrons, with another filled p, s, and f orbital ...
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H-N-H bond angle in ammonia boron trifluoride adduct
In the reaction:
$\ce{NH3 + BF3 -> NH3-BF3}$ does the HNH bond angle increase or decrease?
Surely, the FBF bond angle decreases because boron changes from $\ce{sp^2 -> sp^3}$. But how can we ...
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What proof is there that the "Island of Stability" exists?
Often I see people talking about an "Island of Stability" existing for super-heavy elements on the periodic table, but I don't see any reason to thinks this exists? Surely the heavier you go the more ...
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Will O or S accept an electron more easily?
O has more electronegativity than S but S has more Electron Gain enthalpy than O. How do we decide, which one pulls the electron more easily? In other words, Electron gain enthalpy dominates or ...
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Why is ionisation energy of bismuth lower than lead?
Why is ionisation enthalpy of Bismuth less than that of Lead for it just comes after the latter in periodic table?
First ionisation energy of bismuth is 703 kg/mol while that of lead is 715 kg/mol.
I ...
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