A sample initially contains 3.6 moles of a radioactive isotope. How much of the sample remains after four half-lives

Endeleev saw trends in the physical and chemical properties of elements when he organized them by

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.

In pqr m< p=60 m< q= 30 and m