Question

The correct order of increasing ionic character is (1) \(\mathrm{BeCl}_{2}>\mathrm{MgCl}_{2}>\mathrm{CaCl}_{2}>\mathrm{BaCl}_{2}\) (2) \(\mathrm{BeCl}_{2}>\mathrm{MgCl}_{2}>\mathrm{BaCl}_{2}>\mathrm{CaCl}_{2}\) (3) \(\mathrm{BeCl}_{2}<\mathrm{MgCl}_{2}<\mathrm{CaCl}_{2}<\mathrm{BaCl}_{2}\) (4) \(\mathrm{BeCl}_{2}<\mathrm{CaCl}_{2}<\mathrm{MgCl}_{2}<\mathrm{BeCl}_{2}\)

Short answer

Option 3:

Step-by-step solution

Understanding Ionic Character

Ionic character refers to the degree to which a bond between two atoms is ionic. In general, the greater the difference in electronegativity between the two atoms, the greater the ionic character.

Analyze Electronegativity of Metals

Beryllium (Be), Magnesium (Mg), Calcium (Ca), and Barium (Ba) are all in the same group of the periodic table (Group 2A). As we move down the group, the electronegativity of these metals decreases.

Analyze the Electronegativity Trend

Therefore, the order of increasing ionic character would be will be mostly ionic among the options in the given problem.

Provide the Correct Order

By following our analysis, the correct order of increasing ionic character is: Thus, option 3

Key concepts

headline of the respective core concept

Ionic character is an important concept in chemistry because it helps explain the nature of the bond between two atoms. Simply put, the ionic character of a bond indicates how much it behaves like an ionic bond, where one atom donates an electron to another. This happens when there's a significant difference in electronegativity between the two bonding atoms. The greater the difference, the more ionic character the bond has.

For example, in our exercise, we're looking at bonds between Group 2A metals (like Be, Mg, Ca, and Ba) and chlorine (Cl). To correctly determine the order of increasing ionic character, we need to know their electronegativities and understand how they affect bonding with chlorine.

electronegativity trend

Electronegativity is a measure of an atom's ability to attract and hold onto electrons. This trend is crucial when discussing ionic character. In the periodic table, electronegativity generally increases as you move from left to right across a period and decreases as you move down a group.

For the Group 2A elements in our exercise—Beryllium (Be), Magnesium (Mg), Calcium (Ca), and Barium (Ba)—the electronegativity decreases as you move down the group. Beryllium has the highest electronegativity among them, and Barium has the lowest.

This trend directly affects the ionic character of their chloride compounds. Since chlorine has a relatively high electronegativity, the larger the difference between its electronegativity and that of the metal it's bonding with, the greater the ionic character of the resulting compound. So, compounds of Barium chloride (BaCl2) will have more ionic character than those of calcium chloride (CaCl2), magnesium chloride (MgCl2), and beryllium chloride (BeCl2).

Group 2A elements

Group 2A elements, also known as alkaline earth metals, are known for forming ionic compounds with nonmetals like chlorine. These elements include Beryllium (Be), Magnesium (Mg), Calcium (Ca), and Barium (Ba). As we move down this group in the periodic table, several trends are observed that help us predict the behavior of their compounds.

One important trend is that their atomic size increases. This means that Barium is much larger in size than Beryllium. Another trend is that they have lower ionization energies, making it easier for them to lose electrons and form positive ions. Consequently, the ionic character of their compounds increases as we move down the group.

So, when bonding with chlorine, the order of increasing ionic character is BeCl2 < MgCl2 < CaCl2 < BaCl2, because Ba has the lowest electronegativity and thus the greatest difference in electronegativity with chlorine, resulting in a bond with higher ionic character.