4.4 kg of carbon dioxide gas, CO_ 2 CO 2 , undergoes reversible isothermal expansion at 298\text{ K}298 K from a volume of 22 to 5 \text{ m}^35 m 3 . Assuming ideal gas behaviour, what is the total work performed by the gas

In any atom of any element, you will find protons and neutrons in the nucleus of any atom 

Ithink the correct answer is 3

The heat added represents an energy change.

So the main goal for the elements is stability which is a complete/full valence shell and typically the magic number for a stable element is 8 valence electron but not always. so elements to the left of the periodic table tend to be way less stable then those on the right, so the elements on the left are much more reactive.