The correct description for an atom of helium would be option C. An atom of helium has its valence electrons in its first energy level, it wouldn't and can't satisfy the Octet rule as it only has 2 electrons, but with 2, it has a full shell, as the first energy level can hold only 2 electrons.
Erm i’m afraid we need the list
Hot air balloons have hot air inside them, which is less dense as the air around it. Thus it rises. A cold air balloon would sink because the air would be more dense than the air around it. Also, the balloon’s volume would vary in size depending on the weight of the balloon.
Answer:1. In Glucose: C : H : O = 1 : 2 : 1
2. In Sulfuric acid: H : S : O = 2 : 1 : 4
3. In Butene: C : H = 1 : 2
