Answer:
magnesium
Explanation:
magnesium is in Group 2, in the periodic table. this means that it has 2 valence electrons. the less valence electrons an element or atom has, the more reactive. Selenium has 6 valence electrons. as a result, Mg is more reactive
The atomic radius increases as you would go down a particular group on the periodic table of elements. This is because along with a greater number of protons, there would also be electrons as well, and thus the need of electron shells surrounding the atom would also be required, to compensate for the more electrons, as according to the bohr model, each shell contains 8 electrons in its electron shell. Thus the distance from the nucleus to the outermost shell increases, the atomic radius.
An ionic bond is formed between lithium and bromine.
I don’t know if I am right but I think it is symbol for the first one and the second one is formula.
Complete Question
The complete question is shown on the first uploaded image
Answer:
The equilibrium constant is 
Explanation:
From the question we are told that
The chemical reaction equation is

The voume of the misture is
The molar mass of
is a constant with value of 
The molar mass of
is a constant with value of 
The molar mass of
is a constant with value of 
Generally the number of moles is mathematically given as

For 


For 


For 


Generally the concentration of a compound is mathematicallyrepresented as

For 
![Concentration[Fe_2 O_3] = \frac{0.222125}{5.4}](https://tex.z-dn.net/?f=Concentration%5BFe_2%20O_3%5D%20%3D%20%5Cfrac%7B0.222125%7D%7B5.4%7D)
For 
![Concentration[H_2] = \frac{1.815}{5.4}](https://tex.z-dn.net/?f=Concentration%5BH_2%5D%20%3D%20%5Cfrac%7B1.815%7D%7B5.4%7D)

For 
![Concentration [H_2O] = \frac{0.12}{5.4}](https://tex.z-dn.net/?f=Concentration%20%5BH_2O%5D%20%3D%20%5Cfrac%7B0.12%7D%7B5.4%7D)

The equilibrium constant is mathematically represented as
![K_c = \frac{[concentration \ of \ product]}{[concentration \ of \ reactant ]}](https://tex.z-dn.net/?f=K_c%20%3D%20%5Cfrac%7B%5Bconcentration%20%5C%20of%20%5C%20product%5D%7D%7B%5Bconcentration%20%5C%20of%20%5C%20reactant%20%5D%7D)
Considering 
And 
At equilibrium the

