[单选题]
Chromium appears to the right of
t1 wte1k2 oj/b fwd3(j)cih v7 vanadium in the
y45u3 foimjtaktj1s *3 7fya 9periodic table, as shown below:
yat 3stf4uk y7j5 *1f9ojmia3
Which of the following statements is true?
A. Cr atoms always have a higher atomic number and atomic mass than V atoms
B. Cr atoms have a higher atomic mass than V atoms but the atomic number may be lower
C. Cr atoms have a higher atomic number than V atoms but the atomic mass may be lower
D. Cr atoms may have a lower atomic number or atomic mass than V atoms
参考答案:
C
本题详细解析:
Explanation:
The atomic number of Cr is higher than that of V by 1, and its relative atomic mass is also higher by approximately 1. The atomic number is unique for each element and dictates the position of the element in the periodic table; thus, Cr always has an atomic number of 24 and vanadium an atomic number of 23. However, isotopes of an element may have different atomic masses, so an atom of Cr may have a lower atomic mass than an atom of V. This question is categorised as easy since the difference between atomic number and atomic mass and the variation in mass between isotopes of an element are covered extensively in the syllabus.
