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Explain why Li resembles Mg more than Na (diagonal relationship) — JEE Chemistry

AAayushaRai25 Asked 2mo ago 339 views 1 answer

Explain why $Li$ resembles $Mg$ more than $Na$ (diagonal relationship).

1 Answer

NANisha Agarwal ✓ Accepted · 2mo ago ▲ 20

Li and Mg show diagonal relationship due to similar:

  1. Ionic radii: $Li^+ = 76$ pm, $Mg^{2+} = 72$ pm
  2. Charge/radius ratio (polarising power): Both have high charge density
  3. Similarities: Both form nitrides ($Li_3N$, $Mg_3N_2$), both form oxides (not peroxides), both carbonates decompose on heating, both chlorides are covalent and soluble in ethanol.

$$Diagonal relationship due to similar ionic potential = \frac{z}{r}$$

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Discussion (3)

N
Underrated solution. The way you set it up makes it almost obvious.
NabinThapa70 · 2mo ago
R
Plotting it roughly also helps you sanity-check the sign.
RiteshBasnet93 · 2mo ago
AB
For revision — the key formula used here comes up almost every year.
Aditi Banerjee · 2mo ago
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