Valence electrons largely determine the chemical properties of an element.
Answer:

Explanation:
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In this case, for the given chemical reaction:

The standard entropy change is computed by subtracting the products standard enthalpy and the reactants standard enthalpy considering each species stoichiometric coefficients:

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Answer:
Al (s) + 3Fe3+ (aq) ---> Al3+ (aq) + 3Fe2+(aq)
Explanation:
atoms become positive (or less negative) ions when they lose electrons. They become negative (or less positive) ions when they gain electrons, since each electron (e-) has a charge of -1.
So, since Al changes to Al3+ which is positive, it loses electrons. And when Fe3+ changes to Fe2+, it becomes less positive, so it gained electrons.
Now, write the half (balanced) equations:
Al ---> Al3+ + 3e-
Fe3+ + e- ----> Fe2+
To combine both equations, we have to eliminate electrons. To do so, make sure both half equations have the same no. of electrons. We can multiply the equation of Fe by 3 so that it has 3 electrons.
3Fe3+ + 3e- ----> 3Fe2+
Finally, we can combine both equations (remember to eliminate the electrons).
Al (s) + 3Fe3+ (aq) ---> Al3+ (aq) + 3Fe2+(aq)
Check to see if both sides of the equation have equal charges. Ions always have an aqueous state.
Calcium with water:
When a metal reacts with water( cold water or hot water) then the products formed are metal hydroxide and hydrogen gas.
Metal + steam --------> Metal hydroxide + Hydrogen
Calcium reacts with cold water to form calcium hydroxide and hydrogen gas:
potassium with water.
Potassium reacts violently with cold water to form potassium hydroxide and hydrogen gas:
2K(s)+ 2H2O(l) --------> 2KOH(aq) + H2(g) + heat.
In this reaction so much heat is produced get hydrogen gas formed catches fire and burns explosively.