Explanation: Rather than the give the atom its identity. Related questions How do I determine the molecular shape of a molecule? What is the lewis structure for co2? What is the lewis structure for hcn? How is vsepr used to classify molecules? What are the units used for the ideal gas law? How does Charle's law relate to breathing?
What is the ideal gas law constant? But a simplified answer has to do with the energy or speed of the electron. As the electron gets closer to the nucleus, its energy and speed increases.
It ends up moving in a region surrounding the nucleus at a speed that is great enough to balance the attraction that is pulling it in, so the electron does not crash into the nucleus.
Have students answer questions about the illustration on the activity sheet. Students will record their observations and answer questions about the activity on the activity sheet. Students can see evidence of the charges of protons and electrons by doing an activity with static electricity. Note : When two materials are rubbed together in a static electricity activity, one material tends to lose electrons while the other material tends to gain electron.
In this activity, human skin tends to lose electrons while the plastic bag, made of polyethylene, tends to gain electrons.
Hold the plastic strip firmly at one end. Then grasp the plastic strip between the thumb and fingers of your other hand as shown. The plastic will be attracted to your hand and move toward it.
Students may notice that the plastic is also attracted to their arms and sleeves. Let students know that later in this lesson they will investigate why the plastic strip is also attracted to surfaces that have not been charged neutral. Note : If students find that their plastic strip does not move toward their hand, it must not have been charged well enough. Have them try charging their plastic strip by holding it down on their pants or shirt and then quickly pulling it with the other hand.
Then they should test to see if the plastic is attracted to their clothes. If not, students should try charging the plastic again. Tell students that the plastic strip and their skin are made of molecules that are made of atoms.
Tell students to assume that the plastic and their skin are neutral—that they have the same number of protons as electrons. Project the image Charged plastic and hand. Point out that before the students pulled the plastic between their fingers, the number of protons and electrons in each is the same. Then, when students pulled the plastic through their fingers, electrons from their skin got onto the plastic.
Since the plastic has more electrons than protons, it has a negative charge. Since their fingers gave up some electrons, their skin now has more protons than electrons so it has a positive charge.
The positive skin and the negative plastic attract each other because positive and negative attract. Explain to students why the plastic is attracted to the desk. The answer takes a couple of steps, so you can guide students by drawing or projecting a magnified illustration of the plastic and desk.
After pulling the plastic between their fingers, the plastic gains extra electrons and a negative charge. The desk has the same number of protons as electrons and is neutral. When the plastic gets close to the desk, the negatively charged plastic repels electrons on the surface of the desk. This makes the surface of the desk near the plastic slightly positive.
The negatively charged plastic is attracted to this positive area, so the plastic moves toward it. The strips will move away or repel each other. Since both strips have extra electrons on them, they each have extra negative charge. Since the same charges repel one another, the strips move away from each other. Uncheck everything else. In this simulation, you can rub the balloon a little bit on the sweater and see that some of the electrons from the sweater move onto the balloon.
This gives the balloon a negative charge. Since the sweater lost some electrons, it has more protons than electrons, so it has a positive charge. If you move the balloon toward the sweater, it will be attracted. This is like moving the charged plastic strip toward the cloth it was rubbed on. You can also move the balloon toward the wall. The excess negative charge on the balloon repels negative charge on the surface of the wall.
This leaves more positive charge on the surface of the wall. The negatively charged balloon is attracted to the positive area on the wall. This is like moving the charged plastic strip toward the finger. Either do the following demonstration or show the video Balloon and Water. The American Chemical Society is dedicated to improving lives through Chemistry. Skip Navigation. Lesson 4. Engage Show a picture of a pencil point and how the carbon atoms look at the molecular level.
Since neutrons are neither attracted to nor repelled from objects, they don't really interact with protons or electrons beyond being bound into the nucleus with the protons. Even though electrons, protons, and neutrons are all types of subatomic particles, they are not all the same size. When you compare the masses of electrons, protons, and neutrons, what you find is that electrons have an extremely small mass, compared to either protons or neutrons. On the other hand, the masses of protons and neutrons are fairly similar, although technically, the mass of a neutron is slightly larger than the mass of a proton.
Because protons and neutrons are so much more massive than electrons, almost all of the mass of any atom comes from the nucleus, which contains all of the neutrons and protons. The third column shows the masses of the three subatomic particles in "atomic mass units.
Negative and positive charges of equal magnitude cancel each other out. This means that the negative charge on an electron perfectly balances the positive charge on the proton. In other words, a neutral atom must have exactly one electron for every proton. If a neutral atom has 1 proton, it must have 1 electron. If a neutral atom has 2 protons, it must have 2 electrons. If a neutral atom has 10 protons, it must have 10 electrons. You get the idea.
In order to be neutral, an atom must have the same number of electrons and protons. This page was constructed from content via the following contributor s and edited topically or extensively by the LibreTexts development team to meet platform style, presentation, and quality:.
Learning Objectives Describe the locations, charges, and masses of the three main subatomic particles. Determine the number of protons and electrons in an atom.
Define atomic mass unit amu. Electrons Electrons are one of three main types of particles that make up atoms. If an electron was the mass of a penny, a proton or a neutron would have the mass of a large bowling ball!
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