Question

Which statements are consistent with Dalton's atomic theory as it was originally stared? Why? \begin{equation} \begin{array}{l}{\text { a. Sulfur and oxygen atoms have the same mass. }} \\\ {\text { b. All cobalt atoms are identical. }} \\ {\text { c. Potassium and chlorine atoms combine in a } 1 : 1 \text { ratio to form }} \\ {\text { potassium chloride. }} \\ {\text { d. Lead atoms can be converted into gold. }}\end{array} \end{equation}

Short answer

Statements b and c are consistent with Dalton's atomic theory. Statement b aligns with the idea that all atoms of a given element are identical, and statement c aligns with the theory that atoms combine in fixed ratios to form compounds. Statements a and d are inconsistent with the theory.

Step-by-step solution

Understanding Dalton's Atomic Theory

First, recall the main points of Dalton's atomic theory. These include: 1) elements are composed of tiny, indivisible particles called atoms; 2) all atoms of a given element are identical, having the same size, mass, and chemical properties; 3) atoms cannot be created, destroyed, or transformed into atoms of another element through chemical processes; 4) compounds are formed when atoms of different elements combine in fixed ratios.

Evaluate Statement a

Statement a suggests that sulfur and oxygen atoms have the same mass. This statement contradicts Dalton's atomic theory since it states that all atoms of a given element are identical in mass but does not claim that atoms of different elements have the same mass. Therefore, statement a is inconsistent with Dalton's atomic theory.

Evaluate Statement b

Statement b suggests that all cobalt atoms are identical. This is consistent with Dalton's atomic theory, which states that all atoms of a given element are identical in size, mass, and chemical properties.

Evaluate Statement c

Statement c suggests that potassium and chlorine atoms combine in a 1:1 ratio to form potassium chloride. This is consistent with Dalton's atomic theory, which posits that compounds are formed when atoms of different elements combine in fixed ratios.

Evaluate Statement d

Statement d suggests that lead atoms can be converted into gold atoms. This statement is inconsistent with Dalton's atomic theory, which asserts that atoms cannot be transformed into atoms of another element through chemical processes.

Key concepts

Atomic Mass

In the world of chemistry, the concept of atomic mass is foundational. Atomic mass is the weight of an atom, often measured in atomic mass units (amu), reflecting the mass of protons and neutrons predominantly, as electrons contribute negligibly. Dalton's atomic theory is instrumental in informing our understanding of this concept.

While Dalton hypothesized that atoms of a specific element hold identical mass, today we know a more nuanced reality: isotopes exist. Isotopes are variations of elements with differing neutron numbers, hence different atomic masses. Yet, Dalton's insights paved the way for the precise measurement of atomic masses, which is critical for predicting the behavior of atoms in chemical reactions and in forming compounds.

Atomic Theory Consistency

The consistency of Dalton's atomic theory over time speaks volumes about its foundational role in chemistry. Dalton proposed that all atoms of a single element are identical in mass and properties and that atoms can't be altered in chemical reactions to become other elements. Although we've refined these ideas with discoveries like isotopes and nuclear reactions, the core principles of Dalton's atomic theory stand firm.

It is a testament to its robustness that even after more than two centuries, the main tenets remain valid. Understanding the consistency of Dalton's theory sheds light on the principles behind chemical reactions, stability of elements, and the laws of conservation of mass.

Chemical Compounds

Dalton's theory also profoundly affects our understanding of chemical compounds. According to Dalton, these compounds form when different elements combine in simple, fixed ratios, reflecting the fact that compounds are composed of molecules which, in turn, are groups of atoms bonded together.

For example, water is always composed of two hydrogen atoms for every oxygen atom, a 2:1 ratio. This notion is pivotal for stoichiometry, the calculation of reactants and products in chemical reactions. Such consistent ratios allow chemists to predict compound formation and their properties, which is instrumental in fields from materials science to pharmacology.

Atom Indivisibility

A central notion in Dalton's atomic theory is the indivisibility of atoms; he posited that atoms are the smallest particles of matter and cannot be broken down further by chemical means. While this concept has been superceded by the discovery of subatomic particles (protons, neutrons, and electrons), the general idea still holds true for chemical reactions: atoms are not destroyed or created anew, but rather rearranged.

This principle undergirds the law of conservation of mass in chemistry and emphasizes that in order to understand the mechanics of a chemical reaction, one must first grasp the concept of the indivisibility of atoms within such a context.