An example is the cell theory
I pick but I'm not sure about it though 1and3
<u>Answer:</u> The ion formed by lithium element is 
<u>Explanation:</u>
Ions are formed when an atom looses or gains electrons.
If an atom gains electrons, it leads to the formation of negative ions known as anions. For Example: Fluorine gains 1 electron to form
ions.
If an atom looses electrons, it leads to the formation of positive ions known as cations. For Example: Sodium looses 1 electron to form
ions.
Lithium is the 3rd element of the periodic table having 3 electrons.
The electronic configuration of lithium element = 
This element will loose 1 electron to attain stable electronic configuration and will lead to the formation of
ion.
Hence, the ion formed by lithium element is 
Explanation:
First Question:
The equation is given as;
2KClO3 --> 2KCl + 3O2
2 mol of KClO3 produces 2 mol of KCl
Converting 7.6 g of KCl to mol;
Number of moles = Mass / Molar mass = 7.6 / 74.5513 = 0.1019
2 mol = 2 mol
x mol = 0.1019
solving for x;
x = 0.1019 mol of KClO3
converting to mass;
Mass = Number of mol * Molar mass = 0.1019 * 122.55 = 12.48
Correct option = B. 12.5 g
Second Question
The equation is given as;
1N2 + 3H2 --> 2NH3
3 mol of H2 produces 2 mol of NH3
Converting 34.06g of NH3 to mol;
Number of moles = Mass / Molar mass = 34.06 / 17.031 = 2 mol
3 mol = 2 mol
x mol = 2 mol
Solving for x;
x = 6 / 2 = 3 mol of H2
Converting 3 mol H2 to g;
Mass = Number of moles * Molar mass = 3 * 2.016 = 6.048g
Correct option: B. 6.05g