Eg:
A metal cannot be Ag (silver) if its colour is gold.
pH:
Certain metals have a certain pH. We could eliminate certain metals, if, for example, it was alkali. If the metal was alkali (pH 8 – 14) it would be most likely to be a metal from the Group 1 and 2 metals (the alkali metals and the alkali earth metals). We would use universal indicator or litmus paper to find this out, once the metal was reacted in a substance such as water
Melting Points:
Each metal has its unique melting boiling points. You could also test boiling points, but metals have extremely high boiling points, so we probably would not reach these Temperatures in the classroom situation.
We would use a bunsen burner to heat the metal up to temperatures perhaps around 7000 C. if the metal melts, then it must be any metals with an official melting point below 7000 C. If it does not, then it must be a metal with an official melting point above 7000 C.
Melting Points: (All under 7000 C)
Al = 6600 Li = 1800
Zn = 4200 Na = 980
Sn = 2320 Rb = 390
K = 630 Cs = 290
Pb = 3270
Carbon (as diamond and graphite) = sublimes (turns from solid to gas)
Reactions In Water:
Extremely reactive metals (ie Group 1 & 2 metals) will react with water, and most metals would react with acid. If it does in water, then it would be likely to be Group 1 & 2 metals. If it does not, then it will probably be a different metal, such as a transition metal, which is not very reactive.
Gases Released:
Similar to the reactions in water or acid, it could react water and acid with the metal and test what gas is given off. Depending on whether it is hydrogen (a lighted splint pops), it is oxygen (a lighted splint glows) or it is carbon dioxide (puts out a lighted splint), we could eliminate metals using this process.
Softness:
Metals (eg Group 1 metals) are really soft and can be cut quite easily with a knife. If a knife can cut the mystery metal, then it will probably be a Group 1 metal, if it will not cut easily then it will probably be another metal.
Unique Properties:
This is unusual, but could be a solution for what the metal is. For example, potassium burns with a lilac flame in water and glows incredibly brightly in a flame. These are some unique ways of metals, and metals are identifiable by doing this.
Metal Properties:
Reactions In H2O / HCl:
Safety Precautions:
In this section, I am going to explain some precautions I would have to make, and by this, perhaps eliminate some metals that it cannot be.
Highly Reactive Metals:
These are very dangerous metals. For example, Group 1 metals (alkali metals) are incredibly reactive, and even have to be stored in oil so that they do not react with the air around them. This will mean that they will be unlikely to be Group 1 metals, as the school would not put an experiment before our safety.
Poisonous Metals – Dangerous Metals:
It would be unlikely to be some metals, because they may become very dangerous if they become part of an aqueous solution, or if they’re burnt in extreme temperatures.
Non-Reactive Metals:
If a non-reactive metal was used for this experiment, then some of our experiments such as reactions in H2O or HCl, some of the most defining experiments, then we may not find out what the metal is. Especially on colour, pH or softness, other experiments, alone. We would probably get narrower results, but not one defining metal that we know it would be.
Precious Metals:
It would be unlikely to be precious metals, such as gold or silver, because in pure state, pieces of it would be incredibly expensive to use.
Lanthanum / Actinium Series Metals:
It would be unlikely to be these metals, because these metals are either incredibly rare or man-made in laboratories. It would be unlikely that the school would have these at all, never mind to use in experiments.
Overall:
Overall, you can’t predict at all what the metal is, but I could eliminate some metals it couldn’t be.
It shouldn’t be group I or II metals. I think these highly reactive metals wouldn’t realistically be used in some of these experiments. These metals could explode, and the school would want to put our safety before an experiment. Also, it shouldn’t be an unreactive or not very reactive metal. If it was, then some of the better experiments for defining one particular metal, such as the reactions or the gases released, would be useless.
The metal would probably be a transition metal. Whilst these are hard dense metals, they do react with hydrochloric acid and water, but not so violently they could damage our health. The block on the periodic table also is the largest, so it would be the most varied choice of metals for the metal to be. This, to a certain point, is my prediction for the outcome. For it to be a transition element.
