Answer:
C. fluorine (F) and chlorine (Cl)
D. arsenic (As) and antimony (Sb)
Explanation:
In the periodic table , all the elements are arranged according to the atomic number ,
and the elements are placed in groups and periods ,
The elements with similar chemical and physical properties are placed in a common group .
The elements present in the same group have the same number of valence electrons in the valence shell .
Hence , from the given options ,
fluorine (F) and chlorine (Cl) belongs to group 17 with 7 valence electrons in the outermost shell .
arsenic (As) and antimony (Sb) belong to group 15 with 3 valence electrons in the outermost shell .
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The temperature of the gas sample is 813 K.
<u>Explanation:</u>
We have to use the ideal gas equation to find the temperature of the gas sample.
The ideal gas equation is PV = nRT
Pressure, P = 429 mm Hg = 0.56 atm
Volume, V = 560 mL = 0.56 L
R = gas constant = 0.08205 L atm mol⁻¹K⁻¹
Mass = 0.211 g
Molar mass of carbon di oxide = 44.01 g / mol
Moles, n = 
= 0.0047 mol
Now, we have to plugin the above values in the above equation, we will get the temperature as,
T = 
= 813 K
So the temperature of the gas sample is 813 K.
