作者puppybaby (小狗儿)
看板Chemistry
标题[学科] 几题问题
时间Mon May 16 20:49:36 2011
碰到了一些问题想破头,请大家帮忙
1. Which of the following atoms is likely to be radio-active?
A) 13 B) 23 C)27 D) 28 E) 56
C Na Al P Fe
答案是D) 解答写质子与中子数为奇数较不稳定
请问这个意思是??
2. The mole percent of helium is 0.000524. What is the concentration of
helium in parts per million (ppm)?
A) 5.24x10^-2 B) 5.24 C) 5.24x10^-4
D) 5.24x10^-5 E)5.24x10^-3
1ppm
答案是B) 解答写 5.24x10^-4x ______ =5.24x10^-2 ppm =5.24%ppm
10^-6
请问它为甚麽要这样算? 整个看不懂QQ 有其他比较清晰的解法吗??
3. Which one of the following statements is not true？
A) If one electron is removed from the highest occupied orbital of N2，the
bond order decreases.
B) The ionization of molecular hydrogen (H2) is higher than that
of atomic hydrogen(H).
C) The ionization of molecular oxygen (O2) is lower than that of
atomic oxygen(O).
答案是A)
可是A应该是对的吧 那B和C各是甚麽意思呢?
希望大家帮我解答一下
谢谢><
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 125.233.150.94