According to the trademark, there is potassium iodate in the ingredients, and the chemical formula of potassium iodate is KIO3, so the iodine here exists in the compound, indicating the element; Potassium iodate is easy to decompose when exposed to light and heat, and crystalline iodized salt should be sealed and stored to prevent moisture and sun.

The iodine content is 20-50mg/kg,

Each package of qualified iodized salt contains at least 20mg 1000g×400g=8mg.

A: Each package of qualified iodized salt contains at least 8 mg of iodine.

So, the answer is: iodine; Sealed storage, moisture-proof and sun protection; 8.