When elements combine to form compounds, do their properties change?

The properties of the compound can be very different from the properties of the elements that make it up. Example: Hydrogen is highly flammable gas, especially around oxygen. Oxygen is gas that supports your life and feels wonderful in your lungs. Compound of hydrogen and oxygen is not gas, is not flammable, and is dangerous to your life if it gets in your lungs. It is called "water". / / / Example: Sodium is a corrosive metal, explosive in water. Chlorine is a green poisonous gas. Compound of sodium and chlorine is not metal, not explosive in water, not gas, and not poisonous. It is called "table salt".

Idon’t know sorry i don’t know the answer i’m s sorry