Answer:
<em>The</em><em> name of the element is magnesium </em>
I Hope this is right if not so sorry :)
The concentration of A will be <em>0.34 mol·L⁻¹</em> after 60 min.
In a first-order reaction, the formula for the amount remaining after <em>n</em> half-lives is
![\text{[A]} = \frac{\text{[A]}_{0}}{2^{n}}\\](https://tex.z-dn.net/?f=%5Ctext%7B%5BA%5D%7D%20%3D%20%5Cfrac%7B%5Ctext%7B%5BA%5D%7D_%7B0%7D%7D%7B2%5E%7Bn%7D%7D%5C%5C)
If 
∴
Aluminum's outer electron in 3p-orbital is slightly further from the nucleus and protected by 3s-orbital. This causes it to need less energy. Magnesium's outer electron is closer and not protected by an outer orbital.
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Answer: 6100 seconds
Explanation: 6.1 Kiloseconds = 6100 Seconds