Question

(a)
(i) Write the electron-dot structures for sodium, oxygen and magnesium.

(b)
(ii) Show the formation of $N{a}_{2}O$ and $MgO$ by the transfer of electrons.

(c)
(iii) What are the ions present in these compounds?

Answer 1

(a)
Electron dot structure is the structure of an atom showing its valence shell electron by the dots around the atom.

Atom	Valence electrons
Sodium (Na)	1
Magnesium (Mg)	2
Oxygen (O)	6

(b)

Sodium atoms lose one electron to form $N{a}^{+}$ ions while oxygen atoms gain two electrons to form $O^{2+}$ions.​

The two $N{a}^{+}$ ions combine to one $O{2}^{-}$ ion to form $N{a}_{2}O$.
Formation of $N{a}_{2}O$.

Magnesium atoms lose two electrons to form $M{g}^{2+}$ ion while oxygen atoms gain two electrons to form $O^{2-}$ ion.​

The one $M{g}^{2+}$ ion combines to one $O^{2-}$ ion to form $MgO$.


(c)
The ions present in the given compounds are listed in the table:

Compound	Cation	Anion
$N{a}_{2}O$	$N{a}^{+}$	$O^{2-}$
$MgO$	$M{g}^{2+}$	$O^{2-}$