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Protons + Neutrons = Nucleus Electrons “orbit” at various distances from nucleus. Electron configuration [2,8,8]. All material objects are made of atoms An atom is mostly empty space Nucleus contains protons (+) and neutrons (0) strongly held together
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Protons + Neutrons = Nucleus Electrons “orbit” at various distances from nucleus
All material objects are made of atoms • An atom is mostlyempty space • Nucleus contains protons (+) and neutrons (0) stronglyheld together • Electrons (-) are weaklybound to the nucleus and can be easily removed
Check yourself. ____ are the charged parts of an atom. • Only electrons • Only protons c. Neutrons only d. Electrons and neutrons e. Electrons and protons f. Protons and neutrons
Charged vs. Uncharged Particles Charged objects have an unequal number of protons and electrons. The SI unit for charge is the Coulomb, C 1 electron = -1.6 x 10-19 C 1 proton = +1.6 x 10-19 C
Identify the following particles as being charged or uncharged. If charged, indicate whether they are charged positively or negatively. (n = neutron, p = proton, e = electron)
The amount of charge carried by a lightning bolt is estimated at 10 Coulombs. What quantity of excess electrons is carried by the lightning bolt?
The amount of charge carried by a lightning bolt is estimated at 10 Coulombs. What quantity of excess electrons is carried by the lightning bolt? Answer: 6.25 x 1019 electrons Multiply the charge in Coulombs (10 C) by the conversion factor: (1 electron) / (1.6 x 10-19 C). The units of C cancel; the answer is in electrons.
What happens when a charged object comes near a neutral object?
Conductorsare materials that permit electrons to flow freely from atom to atom and molecule to molecule. • insulatorsare materials that impede the free flow of electrons from atom to atom and molecule to molecule.
polarizationis the process of separating opposite charges within an object