Help ASAP. Which of these observations are not explained by kinetic-molecular theory? When a gas is heated, it expands
At very low temperatures gases expand less for a given pressure change than they do at high
temperatures
If the volume of a gas decreases its pressure increases at constant temperature
When gas is added to a ngid container, the pressure inside the container increases

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

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).