Part 1 Directions: Fill in the blanks below using the word bank. This part is worth 8 points.

Atoms are not _______________ or _____________ during a chemical reaction.
Scientists know that there must be the ___________ number of atoms on each ___________ of
the ____________. To balance the chemical equation, you must add _______________ in front
of the chemical _____________ in the equation. You cannot ___________ subscripts in a chemical equation!
Word Bank
same change equation lost
coefficients gained side formulas

Part 2 Direction: Balance the three chemical equations using the steps listed below. This part is worth 6 points.
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