Question

Which of the following statements are true concerning ionic bonding? Select one: a. Ionic bonding occurs between a metal, which has a high affinity for electrons, and a nonmetal, which loses electrons relatively easy. b. CaCl2 forms because Ca2+ is always a more stable species than the calcium atom alone. c. Compounds with ionic bonds tend to have low melting points. d. The electronegativity difference between the bonding atoms of ionic compounds is small since the electrons are not shared but rather held together by electrostatic forces. e. All of the above statements are false.

Answer 1

Answer: $CaCl_2$ forms because $Ca^{2+}$ is always a more stable species than the calcium atom alone

Explanation:

An ionic bond is formed when an element completely transfers its valence electron to another element. The element which donates the electron is known as electropositive element or the metal and the element which accepts the electrons is known as electronegative element or non metal.Thus the electronegativity difference between the bonding atoms of ionic compounds is large.

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.  

In $CaCl_2$ , calcium is having an oxidation state of +2 called as $Ca^{2+}$ cation and chloride $Cl^{-}$ is an anion with oxidation state of -1. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral $CaCl_2$.

Electronic configuration of calcium:

$[Ca]=1s^22s^22p^63s^23p^64s^2$

calcium atom will loose two electrons to gain noble gas configuration and form calcium cation with +2 charge.

$[Ca^{2+}]=1s^22s^22p^63s^23p^6$

Electronic configuration of chlorine

$[Cl]=1s^22s^22p^63s^23p^5$

Chlorine atom will gain one electron to gain noble gas configuration and form chloride ion with -1 charge.

$[Cl^-]=1s^22s^22p^63s^23p^6$

Ionic compounds with ionic bonds tend to have high melting points due to strong coulombic forces between them.