JEE Advanced levelOne or more correct optionsDifficulty 3 of 3pt046
Select the correct statement(s) about periods.
APeriod 6 contains 32 elements.
BPeriod 3 contains 18 elements because the 3d subshell is filled in it.
CBoth elements of period 1 have their last electron in the 1s orbital.
DThe 4f subshell is filled in period 5.
Answer: A, C
Period 6 fills 6s, 4f, 5d and 6p: 2+14+10+6=32, so A is true. Period 3 has only 8 elements since 3d fills in period 4, so B is false. H and He both have 1s electrons, so C is true. The 4f subshell fills in period 6, so D is false.