<u>Answer: </u>The chemical symbol of the element is Sulfur.
<u>Explanation:</u>
The element which is present in third period of the periodic table having four 3p electrons is Sulfur. Sulfur is the 16th element of the periodic table which has 6 valance electrons.
The electronic configuration of this element is: ![[Ne]3s^23p^4](https://tex.z-dn.net/?f=%5BNe%5D3s%5E23p%5E4)
This element is considered as a non-metal because it will accept electrons in order to attain stable electronic configuration.
Hence, the chemical symbol of the element is Sulfur.
<h2>Answer : Law of conservation of mass</h2><h3>Explanation :</h3>
The law of conservation of mass states that in any reaction mass is neither created nor lost it has to remain constant in a system.
In this case, when the reaction setup was done in normal way the mass was lost in surrounding was not considered nor being calculated; whereas when the reaction was studied in a closed system where the gas was collected after the reaction the mass changes was noted down which helped to prove the point of law of conservation of mass and energy.
One can consider an example of soda can where the carbonated drink contains pressurized carbon dioxide gas. when opened the gas bubbles gets lost into the surroundings and we don't measure the mass changes. Instead if the soda can was opened in such a way where the gas evolved was measured then the mass changed would remain the same.
A typical human hair is about 1 million carbon-12 atoms JUST IN WIDTH.
Perhaps when they are trying to find the distance of an asteroid to the Earth to find out whether or not it is a hazard to Earth.
The correct answer should be that Potential energy increases, and kinetic energy increases, since they both increase as the temperature changes.