The 28 is the sum of the protons and neutrons in the element silicon.
ALL silicon atoms have 14 protons in the nucleus, so we can turn this into an equation:
#protons + #neutrons = 28
14 + #neutrons = 28
#neutrons = 14
#protons = 14
<span>Deep geological disposal is widely agreed to be the best solution for final disposal of the most radioactive waste produced.
</span>Geological disposal<span> involves isolating radioactive waste </span>deep<span> inside a suitable rock volume to ensure that no harmful quantities of radioactivity ever reach the surface environment.
</span>
Hope this helps :)
increase the force needed to move the object
Explanation:
If a machine decreases the distance an object moves, it must also increase the force need to move the object.
A machine is a device that is used to do work with a little energy input.
Work done = force x distance
We see that to do more work, a lot of force must be applied to move a body through a greater distance.
If the distance is reduced;
Distance = 
More force must be applied to measure up for the distance and make the machine more efficient.
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Rare earth elements are a series of chemical elements found in the earth's crust and are vital to many of the modern technologies in the world such as computers and networks, advanced transportation and consumer electronics. They help fuel economic growth, maintain high living standards and even save lives. Examples include:
Scandium. Used in television and fluorescent lamps.
Yttrium. Used in cancer treatment drugs, superconductors and camera lenses
Lanthanum. Used to make special optical glasses, telescope lenses and also in petroleum refining.
Neodymium. Used in making some of the strongest permanent magnets, found in most modern vehicles and aircraft.
Salt can be classified as a pure substance as it is only composed of sodium chloride
while contain many other substances
