Which statement describes the law of constant composition (definite proportions)? mass in an isolated system is neither created nor destroyed by chemical reactions. all samples of a given chemical compound will be composed of the same elements in the same proportion. when two elements react to form multiple compounds, the different masses of one element that combine with a fixed mass of the other element can be expressed as a ratio of whole numbers. energy cannot be created or destroyed, but may be changed from one form to another. for a collision occurring between two particles in an isolated system, the total momentum of the two particles before the collision is equal to the total momentum of the two particles after the collision.

All samples of a given chemical compound will be composed of the same elements in the same proportion.

Explanation:

The law of constant composition or definite proportions states that "all pure samples of the same chemical compound contain the same proportions of the elements by mass". For example, every time water H₂O forms, it would always  have the same proportion of hydrogen and oxygen.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

they it depends on if one believes about radioactivity, they make a geiger counter beep but maybe it was going to beep anyway electronics do wierd things all the time or it was programmed to beep near certain metals.