some examples of chemical properties are toxicity and flammability
THE ANSWER IS chemical PROPERTIES
The properties of a substance which can be measured or observed without altering the identity of the substance must be physical properties.
For example if we are heating water sample from room temperature to higher temperature (below the boiling range) the water will get heat up however there will be no change in identity of the water.
In other cases like:
Chemical properties : there may be change in the identity of the substance as it may react with another substance to produce a new substance.
Reactive properties : they are again like chemical properties
phase properties : there are certain phase changes where the identity of substance gets changed. For example the rhombic sulfur changes to monoclinic sulfur.
because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.
so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates