Explanation:
On the whole, the metals burn in oxygen to form a simple metal oxide. Beryllium is reluctant to burn unless it is in the form of dust or powder. Beryllium has a very strong (but very thin) layer of beryllium oxide on its surface, and this prevents any new oxygen getting at the underlying beryllium to react with it
Answer:

Explanation:
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In this case, for the reaction by which water is decomposed to molecular hydrogen and oxygen:

It is necessary to perform the inspection balance process since there is a dissimilar number of atoms of oxygen on both sides; therefore, by putting a 2 on water we balance oxygen:

But now, there are four hydrogens on the left; therefore, we put a 2 on hydrogen to finally balance it:

And obviously, the coefficient in oxygen is an unwritten 1.
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