Chemistry Class 11 Chapter 2 Question Number 2.26 and 2.27
Question 2.26: An atom of an element contains 29 electrons and 35 neutrons. Deduce
(i) the number of protons and
(ii) the electronic configuration of the element.
Answer 2.26: (i) For an atom to be neutral, the number of protons is equal to the number of electrons.
The number of protons in the atom of the given element = 29
(ii) The electronic configuration of the atom is 1s2 2s2 2p6 3s2 3p6 4s1 3d10
Question 2.27: Give the number of electrons in the species H2+, H2, and O2+
Answer 2.27: H2+: Number of electrons present in hydrogen molecule (H2) = 1 + 1 = 2
Number of electrons in = 2 – 1 = 1
H2: Number of electrons in H2 = 1 + 1 = 2
O2+ : Number of electrons present in oxygen molecule (O2) = 8 + 8 = 16
Number of electrons in O2+ = 16 – 1 = 15
