问题 选择题

下列说法正确的是(  )

A.元素的化学性质是由核电荷数决定的

B.元素的种类是由原子的最外层电子数决定的

C.分子和原子的主要区别是在化学变化中,分子可分,原子不可分

D.水和双氧水的性质不同,是因为它们的组成元素不同

答案

A、最外层电子数主要决定元素的化学性质,故A错误;

B、由元素的定义可知,元素的种类是由原子的核内质子数决定的,故B错误;

C、分子和原子的根本区别是在化学变化中,分子可分,原子不可分,故C正确;

D、水和双氧水的性质不同,是因为它们的分子构成不同,结构决定性质,故D错误.

故选:C.

选择题
阅读理解

Jean Francis Grander was perhaps the most daring man who ever lived and perhaps the craziest.His greatest desire was to entertain and amaze people.He measured his success by the number of people who fainted dead away after witnessing his death-defying(极其惊险的)feats.

Grander,a blond Frenchman,toured North America in 1850,billing himself as “Blondin”.Blondin’s gift was excellent balance.This talent.coupled with a great desire to surprise and shock his audiences,made Blondin an incomparable performer.

His most famous feat was walking across Niagara Falls on a tightrope.Blondin’s “stage” consisted of a rope tied 1,100 feet across the falls.The rope hung some 160 feet above the rocks and boiling water below the falls.

Simply walking across the falls was not exciting enough for Blondin;he later had to ride across on a bicycle.Then,in another performance,he calmly walked across blindfolded(被蒙住的眼睛).At still another time,he carried his terrified manager on his back and walked over the falls before thousands of breathless audience.

But Blondin was undoubtedly his own worst critic.He was never satisfied with hfs act and always tried to attract his audience with his balancing feat.One of his most daring walks was made in the darkness of night.Blondin became so famous on his tour through North America that his last performance was attended by an admiring Prince of Wales.

60.Why does the author think that Grander may be the craziest man in the world?

A.Because he enjoyed entertaining people by terrifying them.

B.Because many people died after seeing his feats.

C.Because his greatest desire was to entertain people.

D.Because he was an incomparable performer.

61.What does the underlined word “feat” in this passage mean?

A.excellent performance                                 B.tour

C.famous event                                              D.victory

6 2.What can we infer from the first sentence in the last paragraph?

A.Blondin was very content with his own performance.

B.Blondin was not very very good at criticism.

C.Blondin never thought that his performance was satisfy.

D.Blondin didn’t like criticism.

63.The author’S attitude towards“Blondin”is       .

A.critical                   B.admiring                 C.negative                  D.depressed

64.Which of the following can NOT be drawn from the passage?

A.Blondin’s success had something to do with his character.

B.In order to be Successful,one should be a critic of himself.

C.Blondin conquered his audience simply by his talent.

D.People can get pleasure from a terrifying experience.