Section 1 Chapter 3 Structure of Matter Section Review

The Structure of Thing

There is a large overlap of the world of static electricity and the everyday earth that you lot experience. Dress tumble in the dryer and cling together. You walk across the carpeting to go out a room and receive a door knob shock. You pull a wool sweater off at the stop of the day and see sparks of electricity. During the dryness of winter, you step out of your car and receive a car door shock as y'all try to close the door. Sparks of electricity are seen as you pull a wool blanket off the sheets of your bed. Yous stroke your true cat'due south fur and observe the fur standing upwardly on its end. Bolts of lightning dash across the evening sky during a spring thunderstorm. And most tragic of all, y'all take a bad hair day. These are all static electricity events - events that tin only be explained by an understanding of the physics of electrostatics.

Not only practice electrostatic occurrences permeate the events of everyday life, without the forces associated with static electricity, life equally we know it would be incommunicable. Electrostatic forces - both attractive and repulsive in nature - hold the earth of atoms and molecules together in perfect balance. Without this electric force, material things would not be. Atoms as the building blocks of matter depend upon these forces. And material objects, including u.s. Earthlings, are made of atoms and the acts of continuing and walking, touching and feeling, smelling and tasting, and even thinking is the result of electrical phenomenon. Electrostatic forces are foundational to our beingness.

1 of the chief questions to be asked in this unit of The Physics Classroom is: How can an object be charged and what affect does that charge accept upon other objects in its vicinity? The answer to this question begins with an understanding of the structure of matter. Understanding charge equally a fundamental quantity demands that we take an understanding of the structure of an atom. So nosotros brainstorm this unit with what might seem to many students to be a curt review of a unit from a Chemistry course.

History of Diminutive Construction

The search for the atom began as a philosophical question. Information technology was the natural philosophers of ancient Greece that began the search for the cantlet by request such questions as: What is stuff composed of? What is the construction of cloth objects? Is there a bones unit from which all objects are made? As early as 400 B.C., some Greek philosophers proposed that matter is made of indivisible building blocks known equally atomos . (Atomos in Greek means indivisible.) To these early on Greeks, matter could not exist continuously broken down and divided indefinitely. Rather, there was a bones unit or building block that was indivisible and foundational to its structure. This indivisible edifice block of which all matter was equanimous became known as the atom.

The early on Greeks were only philosophers. They did not perform experiments to test their theories. In fact, science as an experimental subject field did not emerge equally a credible and popular practice until former during the 1600s. And then the search for the atom remained a philosophical inquiry for a couple of millennia. From the 1600s to the nowadays century, the search for the atom became an experimental pursuit. Several scientists are notable; among them are Robert Boyle, John Dalton, J.J. Thomson, Ernest Rutherford, and Neils Bohr.

Boyle's studies (eye to belatedly 1600s) of gaseous substances promoted the idea that there were dissimilar types of atoms known as elements. Dalton (early 1800s) conducted a variety of experiments to evidence that different elements can combine in fixed ratios of masses to form compounds. Dalton subsequently proposed i of the first theories of atomic behavior that was supported by actual experimental bear witness.

English scientist J.J. Thomson'south cathode ray experiments (end of the 19th century) led to the discovery of the negatively charged electron and the first ideas of the structure of these indivisible atoms. Thomson proposed the Plum Pudding Model, suggesting that an atom'south structure resembles the favorite English dessert - plum pudding. The raisins dispersed amidst the plum pudding are coordinating to negatively charged electrons immersed in a body of water of positive charge.

Nearly a decade subsequently Thomson, Ernest Rutherford'southward famous gold foil experiments led to the nuclear model of atomic construction. Rutherford's model suggested that the atom consisted of a densely packed core of positive charge known every bit the nucleus surrounded past negatively charged electrons. While the nucleus was unique to the Rutherford cantlet, fifty-fifty more than surprising was the proposal that an atom consisted generally of empty space. Nearly the mass was packed into the nucleus that was abnormally small compared to the actual size of the atom.

Neils Bohr improved upon Rutherford's nuclear model (1913) past explaining that the electrons were present in orbits exterior the nucleus. The electrons were bars to specific orbits of stock-still radius, each characterized by their own detached levels of energy. While electrons could exist forced from one orbit to another orbit, information technology could never occupy the infinite between orbits.

Bohr's view of quantized energy levels was the precursor to modern quantum mechanical views of the atoms. The mathematical nature of quantum mechanics prohibits a discussion of its details and restricts u.s. to a brief conceptual description of its features. Breakthrough mechanics suggests that an cantlet is equanimous of a diversity of subatomic particles. The three principal subatomic particles are the proton, electron and neutron. The proton and neutron are the virtually massive of the three subatomic particles; they are located in the nucleus of the atom, forming the dumbo core of the atom. The proton is charged positively. The neutron does not possess a charge and is said to exist neutral. The protons and neutrons are bound tightly together inside the nucleus of the atom. Outside the nucleus are concentric spherical regions of space known as electron shells . The shells are the home of the negatively charged electrons. Each shell is characterized by a distinct energy level. Outer shells have college energy levels and are characterized every bit being lower in stability. Electrons in higher energy shells can move downwardly to lower energy shells; this movement is accompanied by the release of energy. Similarly, electrons in lower energy shells can be induced to move to the college energy outer shells by the addition of energy to the atom. If provided sufficient energy, an electron can be removed from an atom and be freed from its allure to the nucleus.

Application of Atomic Structure to Static Electricity

This cursory excursion into the history of atomic theory leads to some important conclusions about the structure of thing that will exist of utmost importance to our written report of static electricity. Those conclusions are summarized here:

• All cloth objects are composed of atoms. There are different kinds of atoms known every bit elements; these elements can combine to class compounds. Different compounds have distinctly different properties. Material objects are composed of atoms and molecules of these elements and compounds, thus providing dissimilar materials with unlike electrical properties.
• An atom consists of a nucleus and a vast region of space outside the nucleus. Electrons are present in the region of infinite exterior the nucleus. They are negatively charged and weakly bound to the atom. Electrons are oftentimes removed from and added to an atom by normal everyday occurrences. These occurrences are the focus of this Static Electricity unit of The Physics Classroom.
• The nucleus of the atom contains positively charged protons and neutral neutrons. These protons and neutrons are not removable or perturbable by usual everyday methods. Information technology would require some form of loftier-energy nuclear occurrence to disturb the nucleus and subsequently dislodge its positively charged protons. These loftier-free energy occurrences are fortunately non an everyday event and they are certainly not the bailiwick of this unit of measurement of The Physics Classroom. 1 sure truth of this unit of measurement is that the protons and neutrons volition remain within the nucleus of the cantlet. Electrostatic phenomenon tin never be explained by the move of protons.

Summary of Subatomic Particles
Proton	Neutron	Electron
In nucleus Tightly Jump Positive Charge Massive	In nucleus Tightly Bound No Accuse Massive	Outside nucleus Weakly Leap Negative Charge Not very massive

A variety of phenomena will be pondered, investigated and explained through the course of this Static Electricity unit. Each phenomenon will be explained using a model of affair described by the to a higher place iii statements. The phenomena will range from a condom balloon sticking to a wooden door to the clinging together of clothes that have tumbled in the dryer to the bolt of lightning seen in the evening sky. Each of these phenomena will be explained in terms of electron movement - both within the atoms and molecules of a material and from the atoms and molecules of one material to those of another. In the adjacent department of Lesson 1 we will explore how electron movement tin be used to explicate how and why objects acquire an electrostatic charge.

Check Your Agreement

Utilize your understanding of accuse to answer the following questions. When finished, click the push button to view the answers.

i. ____ are the charged parts of an atom.

a. Only electrons

b. Only protons

c. Neutrons only

d. Electrons and neutrons

e. Electrons and protons

f. Protons and neutrons

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Source: https://www.physicsclassroom.com/class/estatics/Lesson-1/The-Structure-of-Matter

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