What does the atomic number of an atom represent?
John says: “When water boils, the H–O bonds are broken.” Is he correct?
Xinyi is doing an experiment. A cotton wool soaked in concentrated hydrochloric acid is placed at one end of a glass tube and another soaked in ammonia at the other. A white ring forms closer to the HCl end. Why?
John says, “Solid particles don’t move at all.” Which statement best describes the motion of particles in a solid?
An atom of fluorine has atomic number 9 and mass number 19. What are the subatomic particles in F⁻?
Which statement explains why solids have a fixed shape?