Why is radium more reactive than calcium?
Pleas I’m tired and desperate

Water's surface tension and heat storage capacity are accounted for by its a) orbitals b) weight c) hydrogen bonds d) mass e) size

Alice did an experiment to find the relationship between the angle at which a ray of light strikes a mirror and the angle at which the mirror reflects the light. she placed a ray box in front of a mirror. she changed the angle at which the light from the ray box struck the mirror and noted the corresponding angle at which the mirror reflected the light. which of the following is the dependent variable in this experiment? the mirror used to reflect the light the ray box used as the source of light angle at which the light from the ray box strikes the mirror angle at which the mirror reflects the light from the ray box

One student said that the investigation was not valid (a fair test). write a plan for the investigation that includes improvements to the method and apparatus