Examples of formal charge in the following topics:
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- To assist with this problem, chemists often calculate the formal charge of each atom.
- The formal charge is the electric charge an atom would have if all the electrons were shared equally.
- The formal charge of an atom can be determined by the following formula:
- The oxygen atom in carbon dioxide has a formal charge of 0.
- Depending on the compound, the shifting of electrons may cause a change in formal charges.
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- In the formula for ozone the central oxygen atom has three bonds and a full positive charge while the right hand oxygen has a single bond and is negatively charged.
- The overall charge of the ozone molecule is therefore zero.
- Similarly, nitromethane has a positive-charged nitrogen and a negative-charged oxygen, the total molecular charge again being zero.
- Finally, azide anion has two negative-charged nitrogens and one positive-charged nitrogen, the total charge being minus one.
- The formal charge on an atom may also be calculated by the following formula:
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- Impeachment is an expressed power that allows for formal charges against a civil officer of government for crimes committed in office.
- Impeachment in the United States is an expressed power of the legislature that allows for formal charges against a civil government officer for crimes committed in office.
- The actual trial on those charges, and subsequent removal of an official on conviction on those charges, is separate from the act of impeachment itself.
- After the reading of the charges, the managers return and make a verbal report to the House.
- After hearing the charges, the Senate usually deliberates in private.
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- If the double bond is broken heterolytically, formal charge pairs result, as shown in the other two structures.
- The preferred charge distribution will have the positive charge on the less electronegative atom (carbon) and the negative charge on the more electronegative atom (oxygen).
- Formal charge separation.
- Electronegativity of charge bearing atoms and charge density.
- (High charge density is destabilizing.
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- Oxidation state is the hypothetical charge of an atom if all of its bonds to other atoms were completely ionic.
- For a simple (monoatomic) ion, the oxidation state is equal to the net charge on the ion.
- Do not confuse the formal charge on an atom with its formal oxidation state, as these may be different (and often are different, in polyatomic ions).
- For example, the charge on the nitrogen atom in ammonium ion NH4+ is 1+, but the formal oxidation state is -3—the same as it is for nitrogen in ammonia.
- In the case between ammonium and ammonia, the formal charge on the N atom changes, but its oxidation state does not.
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- The electronic structure can be described by a relatively ionic model that ascribes formal charges to the metals and ligands.
- The chemical applications of group theory can aid in the understanding of crystal or ligand field theory, by allowing simple, symmetry-based solutions to the formal equations.
- A charge transfer band entails promotion of an electron from a metal-based orbital into an empty ligand-based orbital (Metal-to-Ligand Charge Transfer or MLCT).
- The overall charge of the system remains the same, but the localization of the electron changes.
- Discuss the relationship between charge transfer and the color of a metal complex.
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- Charge separation, often referred to as static electricity, is the building of space between particles of opposite charges.
- All matter is composed of atoms made up of negatively-charged electrons and positively-charged protons.
- In physics, there are many other instances of charge separation that cannot be written as formal chemical reactions.
- Thus, the opposite charges attract.
- Charge separation can be created not only by friction, but by pressure, heat, and other charges.
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- The first two, Gauss's law and Gauss's law for magnetism, describe how fields emanate from charges and magnets respectively.
- Gauss's law relates an electric field to the charge(s) that create(s) it.
- The field (E) points towards negative charges and away from positive charges, and from the microscopic perspective, is related to charge density (ρ) and vaccuum permittivity (ε0, or permittivity of free space) as:
- Gauss's law for magnetism states that there are no "magnetic charges (or monopoles)" analogous to electric charges, and that magnetic fields are instead generated by magnetic dipoles.
- Such dipoles can be represented as loops of current, but in many ways are similar in appearance to positive and negative "magnetic charges" that are inseparable and thus have no formal net "magnetic charge."
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- Dielectric polarization is the phenomenon that arises when positive and negative charges in a material are separated.
- A dielectric is an insulator that can be polarized by an electric field, meaning that it is a material in which charge does not flow freely, but in the presence of an electric field it can shift its charge distribution.
- Positive charge in a dielectric will migrate towards the applied field, while negative charges will shift away.
- Ionic compounds are those that are formed from permanently charge-separated ions.
- For example, table salt (NaCl) is formed from Na+ and Cl- ions that are not formally bound to one another through a chemical bond, but interact very strongly due to their opposite charges.
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- The positive electric charge of a proton is equal in magnitude to the negative charge of an electron; therefore, the net electric charge of an ion is equal to its number of protons minus its number of electrons.
- They are repelled by like electric charges and are attracted to opposite charges.
- Conventionally the net charge is written with the magnitude before the sign; the magnitude of singly charged molecules/atoms is generally omitted.
- Monoatomic ions are sometimes also represented by Roman numerals, which designate the formal oxidation state of the element, whereas the superscripted numerals denote the net charge.
- Sodium has a +1 charge because sodium has eleven electrons.