# What are two elements that would have properties similar to beryllium?

Aug 31, 2017

Probably the two elements with properties most like beryllium are magnesium and aluminium.

#### Explanation:

As you might expect, they should be close to $\text{Be}$ in the Periodic Table.

$\text{Mg}$ is the metal directly below $\text{Be}$ and $\text{Al}$ is diagonally below and to the right of $\text{Be}$.

Several elements in Period 2 have properties like elements diagonally below them and to the right in Period 3. This is called a diagonal relationship.

Here are some comparisons.

$\boldsymbol{\underline{\text{Property"color(white)(mmm)"Beryllium"color(white)(mm)"Magnesium"color(white)(m)"Aluminium}}}$
$\text{Appearance"color(white)(mmll)"shiny"color(white)(mmmmm)"shiny"color(white)(mmmmm)"shiny}$
$\text{Colour"color(white)(mmmmm)"silvery"color(white)(mmmmll)"silvery"color(white)(mmmml)"silvery}$
$\text{Hardness"color(white)(mmmll)"fairly soft"color(white)(mmml)"fairly soft"color(white)(mmm)"fairly soft}$
${\text{Rxn with H"_2"O"color(white)(m)"H"_2 + "Be(OH)"_2color(white)(ll)"H"_2 + "Mg(OH)}}_{2}$
${\text{Rxn with O"_2color(white)(mm)"BeO"color(white)(mmmmmll)"MgO"color(white)(mmmmml)"Al"_2"O}}_{3}$

$\text{Rxn with acids"color(white)(m)"slow because of protective oxide film on surface}$
$\text{Rxn with NaOH" color(white)(l)"Be(OH)"_4^"2-"color(white)(mmmmmmmmmmm)"Al(OH)"_4^"-}$
${I}_{1} \text{/kJ·mol"^"-1} \textcolor{w h i t e}{m m m} 900 \textcolor{w h i t e}{m m m m m m} 738 \textcolor{w h i t e}{m m m m m m} 578$
$E A \text{/kJ·mol"^"-1} \textcolor{w h i t e}{m m m l} 0 \textcolor{w h i t e}{m m m m m m m} 0 \textcolor{w h i t e}{m m m m m m l l} 42$