Step 1-Count the number of atoms of each element on each side of the arrow.
Step 2-Balance atoms using coefficients.
Step 3-Check your work.
1. Na + MgF2  NaF + Mg

2. Mg + HCl  MgCl2 + H2

3. Cl2 + KI  KCl + I2

1) 2Na + MgF2 —> 2NaF + Mg. Explain: You first look at how many F are in each side, then balance it, and look at the rest of the elements and balance them. 2) Mg + 2HCl —> MgCl2 + H2. Explain: look at the number of Cl in each side, balance it, and check to make sure both sides have the same amounts of each element. 3) Cl2 + 2KI —> 2KCl + I2. Explain: first look at the number of Cl on each side, and balance it, then look at the number of K on each side, and balance it, then check to make sure both sides are equal.