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