Which element is rare in the earth’s crust, but common in space rocks?

What is the mass of 8 moles of sodium atoms

The diagrams show objects’ gravitational pull toward each other. which statement describes the relationship between diagram x and y? gravity attracts only larger objects toward one another. gravity attracts larger objects only if they are close to one another. if the masses of the objects increase, then the force between them also increases. if distance between the objects increases, then the amount of force also increases.

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.