Arsenic, I believe. Metalloids fall in between metals and nonmetals (usually on the bold line separating the two on the periodic table). And since the metalloid in question has four electron shells and five valence electrons in the outermost shell, you can see that this element is arsenic
CₓHₐ + (x+a/4)O₂ = xCO₂ + a/2H₂O
n(CO₂)=4.69 mg/44.01 mg/mmol = 0.1066 mmol
n(H₂O)=1.10 mg/18.02 mg/mmol = 0.06104 mmol
C : H = 0.1066 : 0.06104*2 = 0.1066 : 0.12208 = 1 : 1.1453 = 7 : 8
C₇H₈ + 9O₂ = 7CO₂ + 4H₂O
C₇H₈
