) what happens when CO2 passed over time water
for short period of time? Explain

 When carbon dioxide is passed through lime water for a short time,it turns lime water milky due to formation of a white precipitate of calcium carbonate.

Explanation:

Carbon dioxide dissolves in water and slowly reacts with water to produce carbonic acid. The cloudy white solution observed when CO2 is bubbled into limewater results from a reaction between Ca(OH)2 and either CO2 or H2CO3 to form an insoluble calcium carbonate precipitate.

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

the atomic mass is the bottom number on the element.

-steel jelly