(1) False, lots of energy is actually produced from nuclear fuel, if we didn't get much then we probably wouldn't use it
(2) False, its burning coal that contributes to acid rain, since it contains sulfur
(3) False again, we can control the reaction with aptly named control rods, which are typically made of boron, to absorb some of the neutrons flying around in the chain reaction
(4) True, radioactive waste is very difficult to dispose of, and is also very dangerous. Sources of radiation can remain so for millions of years
The term isoelectronic atoms means that if the given atoms are neutral, they would have the same number of electrons, which is relative to their sizes. Ions with positive charges are called cations, losing electrons. On the other hand, ions with negative charges are called anions, gaining electrons. The more electrons that the atoms have, the bigger it is in size. Hence, the arrangement of the radii of the atoms would have to be,
e²⁺, d⁺, c , b⁻, a⁻
The arrangement is from smallest to largest.
Over all the size of the crystal depends on how fast magma will harden over time if the magma cools slowly the crystal will be larger than they would if the magma cooled faster