Predict the chemical formula of the ionic compound formed between the following pairs of elements: (b) K and S

Verified step by step guidance

Identify the charges of the ions formed by each element. Potassium (K) is in Group 1 of the periodic table and typically forms a +1 ion (K^+). Sulfur (S) is in Group 16 and typically forms a -2 ion (S^2-).

Determine the ratio of ions needed to balance the charges. Since K^+ has a +1 charge and S^2- has a -2 charge, you will need two K^+ ions to balance the charge of one S^2- ion.

Write the chemical formula by placing the cation first, followed by the anion. Use subscripts to indicate the number of each ion needed to balance the charges.

The chemical formula is written as K_2S, indicating two potassium ions for every one sulfur ion.

Verify that the total positive charge equals the total negative charge: 2(+1) from K^+ equals -2 from S^2-, confirming the formula K_2S is correct.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

54s

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Ionic Compounds

Ionic compounds are formed when atoms transfer electrons, resulting in the formation of positively charged cations and negatively charged anions. These oppositely charged ions attract each other, creating a stable ionic bond. The overall charge of the compound must be neutral, meaning the total positive charge must balance the total negative charge.

Valence Electrons

Valence electrons are the outermost electrons of an atom and are crucial in determining how an element will bond with others. For potassium (K), which has one valence electron, it tends to lose that electron to achieve a stable electron configuration. Sulfur (S), with six valence electrons, typically gains two electrons to complete its outer shell, forming an anion.

Chemical Formula Representation

The chemical formula of an ionic compound reflects the ratio of the constituent ions that results in a neutral charge. For potassium and sulfur, potassium forms a K+ ion and sulfur forms an S2- ion. To balance the charges, two potassium ions are needed for every one sulfur ion, leading to the formula K2S.

Recommended video:

Guided course

02:08

Molecular Formula

Related Practice

Textbook Question

What is the Lewis symbol for each of the following atoms or ions: c. Sn²⁺

Textbook Question

(a) Using Lewis symbols, make a sketch of the reaction between magnesium and oxygen atoms to give the ionic substance MgO

views

Textbook Question

Predict the chemical formula of the ionic compound formed between the following pairs of elements: (d) Mg and N

Textbook Question

Which ionic compound is expected to form from combining the following pairs of elements? c. lithium and nitrogen

Textbook Question

Which ionic compound is expected to form from combining the following pairs of elements? (d) aluminum and oxygen.