Explain the contributions of Meyer and Moseley to the periodic table.

Name: Problem 5, Chapter 9: Chemistry A Molecular Approach
Uploaded: 2020-02-04T01:49:20-08:00
Duration: 3 min 11 s
Channel: Praj Sharma
Description: Explain the contributions of Meyer and Moseley to the periodic table.

Explain the contributions of Meyer and Moseley to the...

Key Concepts

Periodic Law

The periodic law is the principle stating that the properties of elements are periodic functions of their atomic numbers. Meyer’s work, through the analysis of atomic volume trends, reinforced the idea that elemental properties recur in a systematic way, while Moseley's experimental evidence confirmed that the periodicity is based on the atomic number, not atomic mass. Together, their contributions helped solidify the periodic law as the fundamental organizing principle of the periodic table.

Atomic Number Determination

Moseley’s pioneering use of X-ray spectroscopy led to the discovery that each element emits X-rays at frequencies that are directly related to its atomic number. This provided a quantitative and reliable method for ordering elements by their nuclear charge rather than by atomic mass, resolving inconsistencies in earlier periodic tables and establishing atomic number as the definitive property for element classification.

Analysis of Periodic Trends

Meyer's investigations into the relationships between atomic volume and other elemental properties allowed for a clearer understanding of periodic trends within the elements. His work contributed to recognizing the regular recurrence of chemical properties across the elements, supporting a framework where similarities between elements are more systematically and predictably organized in the periodic table.

Transcript

00:01 This video will focus on the contributions of mayor, mendeleve, and moseley on the field of chemistry.

00:06 And more specifically, all three these individuals were ultimately very influential in the development of our modern periodic table.

00:14 So let's start with mayor.

00:15 So mayor first discovered the periodic law.

00:21 So he noticed that certain elements behaved very similarly, and he basically clustered those together.

00:28 So in mendel leaves characterization of elements, he would cluster elements such as, you know, sodium potassium together, fluorine chlorine together, so on and so forth on the basis that they acted very similarly.

00:40 Right.

00:42 Mendelieve then came in and created a primitive periodic table.

00:51 Primitive, periodic.

00:55 And what he would do is he would organize elements into these rows and say, okay, well, you have, you know, this atom, this atom, this atom, and this atom.

01:03 Well, the problem was mendelie organized his periodic table by atomic mass.

01:10 So recall that atomic mass is the sum of protons and neutrons in an atom.

01:15 So he organized his table by atomic mass, and he quickly ran into a problem because he didn't know if he had discovered all the elements within a certain bandwidth.

01:27 So what i mean by that is let's just say he has an element that has an atomic mass of 48.

01:32 And then he finds another one that has 51...

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