Question

Draw the electron dot diagram to show the formation of a stable positive ion from a molecule having two lone pairs of electrons and another atom short of a lone pair of electrons [e.g. ${H^{1 + }}$].

Answer 1

We first need to know what an electron dot diagram is and accordingly draw one such diagram for a stable positive ion from a molecule having two lone pairs of electrons and another atom short of a lone pair of electrons. A lone pair is a pair of valence electrons in a covalent bond that is not shared with another atom.

Complete answer:
Lewis structures, also known as Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures, are diagrams that depict the bonding between atoms in a molecule, as well as any lone pairs of electrons that may be present. Lewis structures add lines between atoms to indicate shared pairs in a chemical bond, extending the notion of the electron dot diagram. The sum of the valence electrons on each atom equals the total number of electrons represented in a Lewis structure. Lewis structures do not include non-valence electrons. The Lewis structure of an ion is enclosed in brackets, and the charge is represented as a superscript outside the brackets on the upper right.
The one such example asked in the question is the formation of hydronium ions. The reaction is as follows:
${H_2}O + {H^ + } \to {H_3}{O^ + }$
In the reaction above, ${H_3}{O^ + }$ is the stable positive hydronium ion which has resulted from water, ${H_2}O$ which has two lone pairs of electrons and ${H^ + }$ atom short of a lone pair of electrons. The electron dot diagrams are given as follows:

Electron dot diagrams of water and hydronium ions.

Note:
Any covalently bound molecule, as well as coordination compounds, can be represented by a Lewis structure but it is worth noting that there are several basic and archetypal molecular systems for which a Lewis description is misleading or erroneous, at least in its original form. Notably, erroneous bond ordering, bond lengths, and/or magnetic characteristics are inferred from naïve Lewis structure drawings for compounds confirmed to have unpaired electrons empirically. The phenomena of aromaticity are likewise not explained by a simple Lewis model.