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ELECTRONIC STRUCTURE OF MATTER

(Activity Sheet for Grade 9)

ADELINDA A. FAJARDO

· Volume III Issue II

Introduction

What makes a rubber ball different from a plastic ball? Why do different materials have different properties? These questions will be answered after reading/doing this module.

The experiment proves that matter consists of different particles called atoms. Man’s mental picture or theory of the atom has undergone many revisions. The development of modern atomic theory is a good example of how a theory undergoes change as more facts become known. 

The most mysterious part of the atom is the electrons. The nucleus is relatively easy to comprehend because we think of it as a core of a positive charge. But the electrons have a lot more space (remember the analogy with the football field) and it is natural to inquire about things like--are the electrons moving or are they stationary? If the electrons are moving, how do they move, and finally, what are electrons? These were questions that occupied the minds of the physicists at the beginning of the 20th century, a period that was probably one of the most interesting and influential in the last 100 years of science. This period was alive with other important discoveries and theories.

Objectives

 At the end of this module, you will be able to:

 Describe the Bohr Model of the atom

 Explain how the Quantum Mechanical Model of the atom describes the energies and positions of the electrons

 Write or draw the electronic structure of atoms

see PDF attachment for more information