Properties and electron arrangement. Going down each column elements have similar properties and as they move left to right have the same number of electrons in their outer shell
        
             
        
        
        
Answer:
Atoms get rearranged and make up different molecules. No atoms are created nor destroyed. 
Explanation:
 
        
             
        
        
        
Answer:
C.) Argon
Explanation:
This is because ionisation energy increases as we move from left to right in a period. Argon presents in the right most column and Argon is a novel gas and has 8 electrons in outermost orbital. So, it is highly stable. I hope I helped! ^-^
 
        
             
        
        
        
Answer:
The temperature of the gas is 876.69 Kelvin
Explanation:
Ideal gases are a simplification of real gases that is done to study them more easily. It is considered to be formed by point particles, do not interact with each other and move randomly. It is also considered that the molecules of an ideal gas, in themselves, do not occupy any volume.
The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:  
P*V = n*R*T 
where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas. 
In this case:
- P= 470 mmHg
- V= 570 mL= 0.570 L
- n= 0.216 g= 0.0049 moles (being the molar mass of carbon dioxide is 44 g/mole)
- R= 62.36367  
Replacing:
470 mmHg*0.570 L= 0.0049 moles* 62.36367  *T
 *T
Solving:

T= 876.69 K
<em><u>The temperature of the gas is 876.69 Kelvin</u></em>