首页
财务会计
医药卫生
金融经济
考公考编
外语考试
学历提升
职称考试
建筑工程
IT考试
其他
登录
职称考试
Learn about Noble Gases (惰性气体) 1 Have you ever ridden on a balloon? Many to...
Learn about Noble Gases (惰性气体) 1 Have you ever ridden on a balloon? Many to...
admin
2020-12-24
32
问题
Learn about Noble Gases (惰性气体)
1 Have you ever ridden on a balloon? Many tourist spots offer balloon rides in order for people to see the beauty of a place from above. A balloon contains a noble gas called helium (氦). Formerly, balloons contained hydrogen but hydrogen is very flammable and dangerous when uncontrolled- Therefore, people shifted to helium, which is safer. Helium is safe because it has the properties of the noble gases.
2 People once believed that noble gases couldn’t chemically react at all. For this reason, they were called inert gases (惰性气体).They were also listed under Group 0 in the old periodic table because scientists believed that the gases have zero valence (价)electrons in their outer shell. This was later proven to be untrue when some noble gas compounds were discovered.
3 The gases are elements, which share similar properties. These properties include being monatomic, colorless, odorless, being able to conduct electricity, and having low chemical reactivity. Noble gases include Helium, Neon, Argon, Krypton, Xenon and Radon. These are all found in Group 18, in the rightmost column of the periodic table. If you look at the periodic table, you will notice that these elements are the only ones, which do not have a charge. Helium has the lowest molecular (分子的)weight while Radon is the heaviest.
4 Remember that chemical reactions occur because atoms have valence electrons, which are electrons in their outer shell. When the outer shell is "unfilled" or the required number of electrons is not yet complete, the atom is more reactive. Noble gases have a full outer shell, meaning that they have complete electrons in their outer shell. This complete number varies. For instance, the outer shell of Helium has 2 valence electrons while the outer shell of Xenon has 8 electrons. Nowadays, there remains to be a few noble gases because of the low chemical reactivity of these said gases.
5 Because of their properties, noble gases have many important applications. They are widely used in medicine and industries. For instance, liquid Helium is used for superconducting magnets (磁体).These magnets are very important in physics and medicine. When a doctor suspects that a person’s brain has been damaged, he might request for Magnetic Resonance Imaging (MRI) . MRI allows the doctor to "see" the brain, without operating on the patient.
Paragraph 3
选项
A What are noble gases?
B What is the periodic table?
C What causes the low chemical reactivityof noble gases?
D How were noble gases discovered?
E How were noble gases understood in thepast?
F What are the applications of noble gases?
答案
A
解析
本段开头介绍了noble gases的相同点,紧接着作者又列出了noble gases包括的气体及它们的特性。
转载请注明原文地址:https://ti.zuoweng.com/ti/kF9QKKKQ
相关试题推荐
LearnaboutNobleGases(惰性气体) 1Haveyoueverriddenonaballoon?Manytou...
LearnaboutNobleGases(惰性气体) 1Haveyoueverriddenonaballoon?Manytou...
LearnaboutNobleGases(惰性气体) 1Haveyoueverriddenonaballoon?Manyto...
LearnaboutNobleGases(惰性气体) 1Haveyoueverriddenonaballoon?spotso行...
LearnaboutNobleGases(惰性气体) 1Haveyoueverriddenonaballoon?spotso行...
LearnaboutNobleGases(惰性气体) 1Haveyoueverriddenonaballoon?spotso行...
LearnaboutNobleGases(惰性气体) 1Haveyoueverriddenonaballoon?spotso行...
LearnaboutNobleGases(惰性气体) 1Haveyoueverriddenonaballoon?spotso行...
LearnaboutNobleGases(惰性气体) 1Haveyoueverriddenonaballoon?Manytou...
LearnaboutNobleGases(惰性气体) 1Haveyoueverriddenonaballoon?Manytou...
随机试题
支气管肺炎患者,以下哪种情况适合应用糖皮质激素 A.中毒症状明显者 B.严重
对于单位不重要的会计凭证可以不必按照规定的程序来办理。( )
基金管理人的职能不包括()。
金融市场是资金融通市场,是指资金供应者和资金需求者双方通过信用工具进行交易而融通
下列关于银行结售汇业务综合头寸管理制度的表述中,正确的有()。
幼儿急疹的临床特点是A.发热1~2天出疹B.热退后全身出疹C.出疹时全身体温升高D.皮疹常有融合E.疹退后皮肤留有棕色色素沉着
体内的药物及其代谢产物从各种途径排出体外的过程为查看材料A.吸收B.分布C.代谢D.排泄E.消除
受国家食品药品监督管理局委托,起草执业药师业务规范的是()。A.国家药典委员会B.中国食品药品检定研究院C.执业药师资格认证中心D.药品评价中心
受行政处罚被注销房地产经纪人员注册证书的,自注销决定作出之日起不满()的,不予注册。A.1年B.3年C.4年D.5年
高某生了一对双胞胎,某县计生办根据省政府以省长令发布的《计划生育管理条例》的规定,以超生为由对其作出罚款5000元的处罚决定,以下说法正确的是: A.高...