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 tou...
Learn about Noble Gases (惰性气体) 1 Have you ever ridden on a balloon? Many tou...
admin
2020-12-24
55
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.
Among the elements of noble gases Helium is the .
选项
A lightest
B reactive
C important
D complete
E flammable
F unnecessary
答案
A
解析
根据第三段最后一句:Helium has the lowest molecular (分子的) weight...
转载请注明原文地址:https://ti.zuoweng.com/ti/LZsQKKKQ
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?Manytou...
LearnaboutNobleGases(惰性气体) 1Haveyoueverriddenonaballoon?Manytou...
LearnaboutNobleGases(惰性气体) 1Haveyoueverriddenonaballoon?Manytou...
随机试题
(70-73题共用备选答案) A.圈形卡环 B.回力卡环 C.联合卡环
12岁女孩,左膝关节弥漫性肿胀已10个月,自觉轻度疼痛,无外伤史,检查见左膝关节
世界上首创心理学实验室的人是
下列关于证券发行市场和证券交易市场关系的说法中,正确的有()。Ⅰ.证券发行市场
根据我国《婚姻法》的规定,协议离婚的条件不包括()。
青紫舌主病不包括
心源性腹水与肝源性腹水的主要鉴别点是 A.颈静脉怒张 B.下肢水肿 C.
参与性概述是指()。 A.咨询师将自己叙述的主题、意见等整理后,简要地表达出来
印模膏具有如下特点,除了A:加热变软冷却变硬B:作为初印模C:弹性好D:可反复使用E:在口腔能耐受的温度下,流动性和可塑性差
下列地面中,属于按照面层材料分类的是( )。A:涂料地面B:防腐蚀地面C:采暖地面D:拼花地面