Question

Which of the following statements are correct?
(i) The second period (n = 2) starts with lithium and third electron enters the 2s orbital. The next element, beryllium has four electrons and has the electronic configuration $1s^{2}2s^2$. From the next element boron, the 2p orbitals are filled with electrons when the L shell is completed at neon $(2s^{2}2p^6)$. Thus there are 8 elements in the second period
(ii) Successive filling of 3s and 3p orbitals gives rise to the third period of 8 elements from sodium to argon.
(iii) The fourth period (n = 4) starts at potassium and the added electron fill up the first 4s and 4p orbitals than 3d orbital is filled
(iv) Fifth period begins with rubidium with the filling of 5s orbital and ends at xenon with the filling up of the 5p orbital

• A. (i) and (ii)
• B. (i), (ii) and (iii)
• C. (iii) and (iv)
• D. (i), (ii) and (iv)

Answer 1

Answer: (B)

Correct answer is (b) (i), (ii) and (iii)