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".
When elements combine to form compounds, the resulting substance has different properties from the individual elements. Compounds are formed in fixed whole numbers proportions and have their own distinct chemical and physical properties, such as sodium chloride being safe to eat despite being made from reactive sodium and poisonous chlorine. ;
When elements combine to form compounds, their properties change significantly. For example, hydrogen and oxygen combine to create water, which has very different properties than the individual gases. Similarly, sodium and chlorine form table salt, which is a non-toxic solid, diverging vastly from their elemental forms.
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