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TOEFL Directory > TOEFL writing > TOEFL Reading Class Unit 2_Passage 18_Question 188-198
TOEFL Reading Class Unit 2_Passage 18_Question 188-198
You have about 15 minutes to finish this passage.
First,use about 3-4 minutes to read the passage, try to understand the main idea of this passage.
Don't read it so slowly or try to remember all details.You need to do "fast reading",and "scan" the passage.
Second, read questions 1-11, and with questions you go back the passage again and look for correct answers.
Question 188-198
Passge 18
By looking at examples of atoms, one discovers that each contains an equal number of electrons and protons in the nucleus. This is normally true of any atom. When in this condition, the atom is considered to be in its balanced state (sometimes referred to as the neutral state).
Atoms can be affected by many outside forces such as heat, light, electrostatic fields, chemical reactions, and magnetic fields. These external forces can upset the balanced atom, and as a result, the atom can gain or lose electrons. When the balanced condition is upset, the number of negative charges no longer offsets the number of positive charges, thus the atom is left with a net charge. An atom that is no longer in its balanced or neutral state is called an ion. The process of changing an atom into an ion is called ionization. Positive ions or negative ions can exist depending on the balance upset. An atom that contains more protons than electrons is called a positive ion. An atom that contains more electrons than protons is called a negative ion.
There are many forces in nature that can dislodge an electron and cause it to become what is known as a free electron. When this condition occurs, the atom is left with one positive charge that is not canceled by a corresponding negative charge. The result is a net positive charge, or a positive ion. When an atom picks up a stray electron, it has one additional negative charge that is not offset by a corresponding positive charge. The result is a net negative charge, or negative ion. The ion still retains all the basic characteristics of the original atom since the protons in the nucleus are not disturbed.
This process of ionization occurs around us every day. The electrical characteristics of many different types of material are determined largely by the number of free electrons and ions within the material. One of the most noticeable effects of ionization is lightning. One of the most common applications of ionization is the storage battery.
188. With which of the following is the passage mainly concerned?
a) The electrical characteristics of materials
b) The forces of nature that affect atoms
c) The process of ionization
d) The organization of the nucleus of an atom
189. The word discovers in the passage is closest in meaning to
a) agrees
b) hears
c) learns
d) remarks
190.
191. The word result in the passage is closest in meaning to
a) consequence
b) fact
c) goal
d) situation
192. The word dislodge in the passage is closest in meaning to
a) dissolve
b) energize
c) position
d) remove
193. It can be inferred that a neutral atom will become a negative ion when it
a) gains more protons than electrons
b) acquires a free electron
c) reestablishes its balance
d) loses its basic characteristics
194.
195.
196.
197. Why does the author mention lightning in paragraph 4 ?
a) To demonstrate the danger posed by ions
b) To give a familiar example of ionization
c) To identify the electrical characteristics of some
materials
d) To illustrate a common use for ions
198.
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