If isotopes are chemically alike but physically different propose which subatomic particles are

All isotopes of the same element have the same number of protons. Number of neutrons in different atoms of the same element is free to vary. Since, different elements react differently, different elements have different numbers of protons. Atoms with the same number of protons and vary neutrons behave chemically similar. The number of electrons in a neutral atom depends on the number of protons. All chemical reactions involve transfer or sharing of electrons it stands to reason, neutrons are NOT responsible for chemical reactivity. It's arguable whether protons or electrons dictate chemical reactivity certainly the SUBATOMIC nuclear particle that dictates reactivity is the PROTON.

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error