1. Common knowledge : Go to the right of periodic table, the atomic radius is decreasing
2. Flurine has 9 protons and lithium has 3 protons. you know that the electron is attracted with the centre of the atom, that's why more proton, more 'energy' that attract to the centre and that's why it make the shape of the atom is smaller
Objects in the fountain appear to be somewhere but isnt
Answer:

Explanation:
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In this case, it is possible to propose an energy balance in order to illustrate how the heat released by the reaction is absorbed by the water:

Thus, since the heat released by the reaction is -112 kJ (-112000 J), it is possible to define the hear absorbed by the water in terms of mass, specific heat and temperature change:

In such a way, it is possible to define the final temperature as shown below:

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