WHOEVER HELPS WILL GET BRANLIEST 1. Which element has 2 electrons in the 4s energy level
2. The ion with a 2- charge in the 3rd energy level
3. This nonmetal is likely to form an ion with a 3- charge that has the highest IN in the group
4. A metalloid in period 4 with 2 electrons in the p sub level
5. The smallest of the -2 ions

1. is calcium 2,,,halogens 3 group 16 valence electrons non metal.4 .selenium

Explanation:

5. Palio atomic or monatomic hope tgis helps ig right give braniest

that tool would be a compass

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.