Answer:
all of them have seven valence electron
Mass, air has that. Since what fills up a balloon? A gas
Shape, it has no definite shape. This one is accurate, it has no definite shape, it takes the shape of the object it's in.
Volume, does air take up space? If it does then yep. Balloon example/
Density, yes it does, because it's tightly wounded up.
D
Answer : Option 1) nuclei of
and nuclei of
only.
Explanation : Radiation is spontaneously emitted from nuclei of
because this isotope of hydrogen is highly radioactive as compared to other isotopes of hydrogen namely; nuclei of
and nuclei of
.
They have much stable nucleus as compared to nuclei of
.
The more it is unstable the more radiations will be emitted from its nucleus.