Solids: have fixed shape and fixed volume
Liquids: have fixed volume
Gases: have neither fixed volume or fixed shape
This tells you that having a fixed shape is the most responsible characteristic of a solid's structure.
There are multiple answers to this question depending on what answer it's looking for. This is one of the right answers but I don't know if it's the one the question is looking for.
Answer:
The mass number of an isotope is indicated in the name of the isotope by writing the name of the element followed by a hyphen and the mass number.
Explanation:
Examples include carbon-14, uranium-235, and oxygen-17.
Nobel gas, it is in the last row of the periodic table and therefore is a noble gas
H2O is the correct answer :)