Find your element on the periodic table. Locate the element’s atomic number.
Determine the number of electrons. Look for the atomic mass of the element. Subtract (-) the atomic number from the atomic mass
1. Diatomic
2. Products
3. Reactants
4. Coefficient
5. Subscript
6. True
7. False
8. First you must write the reactants. Ensure the valencies of the reactants are correct. Draw an arrow. Write the products. Ensure the valencies of the products are correct and apply subscripts as necessary. Balance the equation by ensuring both sides have equal amounts of each elements - use only coefficients to complete this NOT subscripts.
The molarity of a solution : 0.4 M
<h3>Further explanation</h3>
Given
0.2 moles of Potassium Oxide
500 ml of water = 0.5 L
Required
The molarity
Solution
Molarity is a way to express the concentration of the solution
Molarity shows the number of moles of solute in every 1 liter of solution or mmol in each ml of solution

Assume volume of solution = volume of water(addition of solution volume from volume Potassium Oxide is negligible
Input the value :
M = 0.2 : 0.5
M = 0.4
Protons and neutrons and it is located in the nucleus