To classify the compounds as ionic or covalent, we need to consider the types of elements involved and their electronegativities.
a) MgCl2
Magnesium chloride (MgCl2) is an ionic compound. This is because magnesium is a metal that tends to lose electrons and form cations (Mg2+), while chlorine is a non-metal that gains electrons to form anions (Cl–). The electrostatic attraction between the oppositely charged ions forms the ionic bond.
b) NO2
Nitrogen dioxide (NO2) is a covalent compound. Both nitrogen and oxygen are non-metals, and they share electrons to achieve a stable electronic configuration. The bonds formed between the nitrogen and oxygen atoms are covalent in nature, specifically polar covalent due to the difference in electronegativity between the two elements.
c) SF4
SF4 or sulfur tetrafluoride is also a covalent compound. Both sulfur and fluorine are non-metals, leading to the sharing of electrons. The electronegativity difference between sulfur and fluorine results in polar covalent bonds, where fluorine attracts the shared electrons more strongly than sulfur.
d) KCl
Potassium chloride (KCl) is another ionic compound. Potassium is a metal that readily loses an electron to form K+, while chlorine, being a non-metal, gains an electron to become Cl–. The resulting electrostatic force between these charged ions forms the ionic bond in KCl.
In summary:
- MgCl2: Ionic
- NO2: Covalent
- SF4: Covalent
- KCl: Ionic