Answer:
Noble gases are the least reactive of all elements
Explanation:
because they have eight valence electrons, which fill their outer energy level
Answer:
Incorrect
Explanation:
X is the reactants
Y is the products
In an endothermic reaction where energy is absorbed, the enthalpy the products (Y) is always higher than the enthalpy of the reactants (X).
Enthalpy change (∆H) = products (Y) - Reactants (X)
For an endothermic reaction, the ∆H value should be positive.
Enthalpy change
The diagram sketched by the students shows the opposite. The diagram shows that the enthalpy of the products (Y) is lower than the enthalpy of the reactants (X). This will give a negative value of ∆H.
It represents an exothermic reaction rather than endothermic.
Therefore, the student is incorrect.
<span>About a fifth of the air is made up of oxygen, and almost all the rest is nitrogen. But the origins of the relatively high nitrogen content of Earth’s air have been something of a mystery.</span>
The alkali metals are the most reactive metals. Group 2 consists of the alkaline Earth metals. They are very reactive but less so than the alkali metals.
