文章主講 Angela, Wesley
There are dozens of metals among the 98 natural elements. Some are plentiful and highly useful, like copper, iron, and aluminum. Others are rare and dangerous to use, like mercury, lead, and arsenic. Some metals are so inexpensive that they are sold by the ton. Others are extremely expensive and sold by the ounce, like silver, platinum, and gold. Among them, gold has long been the standard for wealth.
All the natural elements are formed by atoms, which are composed of at least two particles: a proton and an electron. A third kind of particle, neutrons, can also add a bit of variety to atomic structures. The first two are essential for a stable atom. Electrons—particles of negatively-charged energy—revolve around the core. The number of protons of each atom determines how it will be expressed in the physical world.
For millennia, alchemists have tried to create gold, which has 79 protons, through chemical means. They all failed. Surprisingly, however, you can create gold by adding one proton to a platinum atom, which has 78 protons, or by eliminating one proton from mercury, which has 80 protons. Nevertheless, you wouldn’t want to try either method.
The only way to add or subtract protons from an atom is by means of a nuclear reaction. This requires massive amounts of energy. In nature, metals heavier than iron, including gold, were created by the destructive explosion of whole stars. Such power on Earth can be realized only inside a nuclear reactor, and on a microscopic scale. Worse still, the tiny amounts of gold produced would be radioactive and poisonous to the touch!
So until another discovery is made, you’ll just have to enjoy the gold that already exists in the world.
1. According to the passage, which of the following statements is true?
(A) Most gold on the market is produced through a nuclear reaction.
(B) A particular method can produce gold from mercury or platinum.
(C) Alchemists have successfully massproduced gold from other elements.
(D) Metals like copper and iron become poisonous when in contact with gold.
2. What is the purpose of the second paragraph?
(A) To give an introduction to the composition of an atom.
(B) To explain why the physical world is composed of atoms.
(C) To contrast the difference between natural and lab-created gold.
(D) To provide a historical perspective on the development of chemistry.
3. Why does the author suggest that we wouldn’t want to try any of the methods to create gold?
(A) The ingredients are extremely rare and expensive.
(B) The elements would emit radiation during the process.
(C) It is impossible to change the number of protons in an element.
(D) It involves a destructive procedure that makes the final product poisonous.
Ans: 1. B 2. A 3. D