Answer:
hope it's help you ok have a good day
 
        
             
        
        
        
Krypton. The atomic radius decreases as you go across a period.
        
             
        
        
        
The hydrogen one because who doesnt like snoballs'
        
             
        
        
        
Answer:
The correct option is: <u>B. 366 torr</u>
Explanation:
Given: <u>On the ground</u>- Initial Volume: V₁ = 8.00 m³, Initial Atmospheric Pressure: P₁= 768 torr; 
<u>At 4200 m height</u>- Final Volume: V₂ = 16.80 m³, Final Atmospheric Pressure: P₂ = ?
Amount of gas: n, and Temperature: T = constant
<u>According to the Boyle's Law</u>, for a given amount of gas at constant temperature:         P₁ V₁ = P₂ V₂
⇒  P₂ = P₁ V₁ ÷ V₂
⇒  P₂ = [(768 torr) × (8.00 m³)] ÷ (16.80 m³)
⇒  P₂ = 365.71 torr ≈ 366 torr
<u>Therefore, the final air pressure at 4200 m height: P₂ = 366 torr.</u>
 
        
             
        
        
        
70.306 would be your answer.