To balance Ca + Cl2 = CaCl2 you'll need to be sure to count all of atoms on each side of the chemical equation.
Once you know how many of each type of atom you can only change the coefficients (the numbers in front of atoms or compounds) to balance the equation for Calcium + Chlorine gas.
Valence (outermost) electrons. Chemical bonds are formed when an atom does not have a full outermost shell, i.e. there are 7 electrons and 1 more is needed, or there is only 1 electron, which can be transferred to another atom.
The empirical formula is K₂CO₃.
The empirical formula is the <em>simplest whole-number ratio of atoms</em> in a compound.
The ratio of atoms is the same as the ratio of moles, so our job is to calculate the <em>molar ratio of K:C:O</em>.
I like to summarize the calculations in a table.
<u>Element</u> <u>Moles</u> <u>Ratio</u>¹ <u>Integers</u>²
K 0.104 2.00 2
C 0.052 1.00 1
O 0.156 3.00 3
¹ To get the molar ratio, you divide each number of moles by the smallest number.
² Round off the number in the ratio to integers to integers (2, 1, and 3).
The empirical formula is K₂CO₃.