Question

Describe the similarities between H3O and NH3. Compare/contrast their shapes and polarities within the context of your answer. These molecules are called isoelectronic. Why

Answer 1

Answer:

Explanation:

$H_3O^+$ also known as hydronium ion is formed as a result of the reaction between an hydrogen proton and a water molecules.

i.e $\mathtt{H^+ + H_2O \to H_3O^+}$

(molecular geometry for the hydronium ion shows that the lewis structure of hydronium ion possess a three hydrogen ion bonded to a central atom known as oxygen. The oxygen possess a lone pair with a positive ion. So we have three hydrogen atoms and a lone pair attached to the oxygen. We can now say that there are four groups as the steric number in which one of them is a lone pair. This give rise to the trigonal pyramidal shape of the $H_3O^+$ (hydronium ion) with a bond angle of about 109,5°

Similarly, $NH_3$ on the other hand also known as ammonia has a shape that can be also determined by the Lewis structure.

IN ammonia,  there are three hydrogen  and a lone pairs of electron spreading out as far away from each other  from the centre nitrogen. In essence, the valence shell electron pair around hydrogens tend to repel each other. Hence, giving it a trigonal pyramidal shape.

From above the similarities between H3O and NH3 is in their molecular geometry in which both  H3O and NH3 have the same shape.

These molecules are called isoelectronic. Why?

Isoelectronic molecules are molecules having the same number of electrons and same electronic configuration  structure. As a result H3O and NH3 possess the same  number of electrons in the same orbitals and they also posses the same structure.