An isotope is one of two or more species of atoms of a chemical element with the same atomic number (same number or protons in the nucleus) and position in the periodic table and nearly identical chemical behavior but with different atomic masses and physical properties. Every chemical element has one or more isotopes.
A landslide is the movement of rock, debris or earth down a slope. They result from the failure of the materials which make up the hill slope and are driven by the force of gravity. Landslides are known also as landslips, slumps or slope failure.
Land area that delivers water, sediment, and dissolved substances via small streams to a major stream (river). If a drop of rain falls anywhere within a watershed, it can flow out only through that same stream or river.hapter 16, Landslide is a general term for the down slope movement of soil and rock. Landslides occur when the driving forces that tend to movie soil, rock, vegetation, houses, and other materials down a slope exceed the resisting forces that hold the slope in place.