Periodic Classification and Periodic Properties - Result Question 2
####3. The statement that is not correct for the periodic classification of elements, is
(1992, 1M)
(a) the properties of elements are the periodic functions of their atomic numbers
(b) non-metallic elements are lesser in number than metallic elements
(c) the first ionisation energies of elements along a period do not vary in a regular manner with increase in atomic number
(d) for transition elements the d-subshells are filled with electrons monotonically with increase in atomic number
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Answer:
Correct Answer: 3. (d)
Solution:
- (a) Correct statement According to Moseley’s law, the properties of elements are the periodic function of their atomic numbers.
(b) Correct statement The whole $s$-block, $d$-block, $f$-block and heavier $p$-block elements are metal.
(c) Correct statement Trend is not regular, Be has higher first ionisation energy than $B$, nitrogen has higher first ionisation energy than oxygen.
(d) Inccorrect statement $d$-subshells are not filled monotonically, regularity break at chromium and copper.
