Electric Charge

• Static electricity events in everyday life include clothes clinging together in the dryer, receiving a shock from a doorknob after walking across carpeting, seeing sparks of electricity when pulling off a wool sweater, and experiencing a car door shock during dry winter weather
• Electrostatic forces hold the world of atoms and molecules together, essential for the existence of material things and life itself
• The history of atomic structure includes the early Greek concept of atomos as indivisible building blocks of matter, leading to experimental pursuits by scientists like Robert Boyle, John Dalton, J.J. Thomson, Ernest Rutherford, and Neils Bohr
• J.J. Thomson's cathode ray experiments led to the discovery of the electron and the Plum Pudding Model of the atom, while Ernest Rutherford's gold foil experiments proposed the nuclear model of atomic structure
• Neils Bohr improved upon Rutherford's model by suggesting electrons were present in orbits outside the nucleus, each characterized by discrete energy levels
• Quantum mechanics views atoms as composed of subatomic particles: protons, neutrons, and electrons, with protons and neutrons in the nucleus and electrons in electron shells outside the nucleus
• An atom is composed of a nucleus with protons and neutrons, and electrons outside the nucleus; electrons can be removed or added to an atom by everyday occurrences
• Atoms are composed of protons, neutrons, and electrons; protons are positively charged, neutrons are neutral, and electrons are negatively charged
• Atoms are electrically neutral when they have an equal number of protons and electrons; if an atom has an unequal number of protons and electrons, it becomes electrically charged and is referred to as an ion
• Positively charged particles possess more protons than electrons, negatively charged particles possess more electrons than protons, and uncharged particles have an equal number of protons and electrons
• Electrons are migrants, constantly moving between atoms in different materials, requiring an energy source, motive, and low-resistance pathway for movement
• Objects that are charged contain unequal numbers of protons and electrons
• Charged objects have an imbalance of charge - either more negative electrons than positive protons or vice versa
• Neutral objects have a balance of charge - equal numbers of protons and electrons
• Objects with more electrons than protons are charged negatively; objects with fewer electrons than protons are charged positively
• The charge of an object is measured in Coulombs (C), with units like microCoulombs (µC) or nanoCoulombs (nC) being more commonly used
• One Coulomb of charge is an abnormally large quantity, so smaller units like microCoulombs or nanoCoulombs are used
• The charge on a single electron is -1.602 x 10 -19 Coulomb; the charge on a single proton is +1.602 x 10 -19 Coulomb
• To determine the total charge of a positively charged object, subtract the total number of electrons from the total number of protons
• Interaction between charged objects: oppositely charged objects attract, like-charged objects repel
• Interaction between charged and neutral objects: any charged object will have an attractive interaction with a neutral object
• Repulsion between objects indicates they are both charged with the same type of charge
• Attraction between objects indicates at least one of the objects is charged