I think it’s B. I’m not 100% sure but I believe it is B! Srry if this is late btw.
Atoms with the same number of protons, but different numbers of neutrons are isotopes of the same element.
1) The trails left by an electron as it moves around the nucleus
The electron model dictates that the electrons have no fixed position so it traces their path.
2) 8
Atomic number is equivalent to proton number
3) Its mass is lowered, but it is still the same element.
The element's identity is due to the number of protons; however, neutrons play a large role in an atom's mass. Thus, the mass will decrease but the element will be the same. Such variants are called isotopes.
Compound made up of hydrogen and carbon
Answer:
The value is 
Explanation:
From the question we are told that

The initial volume of the fluorocarbon gas is 
The final volume of the fluorocarbon gas is
The initial temperature of the fluorocarbon gas is 
The final temperature of the fluorocarbon gas is 
The initial pressure is 
The final pressure is 
Generally the equation for adiabatically reversible expansion is mathematically represented as
![T_2 = T_1 * [ \frac{V_1}{V_2} ]^{\frac{R}{C_v} }](https://tex.z-dn.net/?f=T_2%20%3D%20%20T_1%20%20%2A%20%5B%20%5Cfrac%7BV_1%7D%7BV_2%7D%20%5D%5E%7B%5Cfrac%7BR%7D%7BC_v%7D%20%7D)
Here R is the ideal gas constant with the value

So
=> 
Generally adiabatic reversible expansion can also be mathematically expressed as

=>
=> 
=>
So

=> 