The octet rule is a chemical rule of thumb that reflects the theory that main-group elements tend to bond in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas. The rule is especially applicable to carbon, nitrogen, oxygen, and the halogens, although more generally the rule is applicable for the s-block and the p-block of the periodic table. Other rules exist for other elements, such as the duplet rule for hydrogen and helium, or the 18-electron rule for transition metals. The valence electrons can be counted using a Lewis electron dot diagram as shown below for carbon dioxide: The electrons shared by the two atoms in a covalent bond are counted twice, once for each atom. In carbon dioxide, each atom shares four electrons with the central carbon, two (shown in red) from the oxygen itself, and two (shown in black) from the carbon. All four of these electrons are counted both in the carbon octet and the oxyg...

 Solid-state physics is the study of rigid matter, or solids, through methods such as quantum mechanics, crystallography, electromagnetism, and metallurgy. It is the largest branch of condensed matter physics. Solid-state physics studies how the large-scale properties of solid materials result from their atomic-scale properties. Thus, solid-state physics form the theoretical basis of materials science. It also has direct applications, for example in the technology of transistors and semiconductors. Solid materials are formed from densely packed atoms, which interact intensely. These interactions produce the mechanical (e.g. hardness and elasticity), thermal, electrical, magnetic and optical properties of solids. Depending on the material involved and the conditions in which it was formed, the atoms may be arranged in a regular, geometric pattern (crystalline solids, which include metals and ordinary ice water) or irregularly (an amorphous solid such as common window glass). The bul...

 In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of a solute to form such solution. The extent of the solubility of a substance in a specific solvent is generally measured as the concentration of the solute in a saturated solution, one in which no more solute can be dissolved. At this point, the two substances are said to be at solubility equilibrium. For some solutes and solvents, there may be no such limit, in which case the two substances are said to be "miscible in all proportions" (or just "miscible"). The solute can be a solid, or a liquid, or a gas, while the solvent is usually solid or liquid. Both may be pure substances, or may themselves be solutions. Gases are always miscible in all proportions, except in very extreme situations, and a solid and liquid can be "dissolved" in a gas only by passing into the gaseous state ...

 Bioethics is both a field of study and professional practice, interested in ethical issues related to health (primarily focused on the human, but also increasingly includes animal ethics), including those emerging from advances in biology, medicine, and technologies. It proposes the discussion about moral discernment in society (what decisions are "good" or "bad" and why) and it is often related to medical policy and practice, but also to broader questions as environment, well-being, and public health. Bioethics is concerned with the ethical questions that arise in the relationships among life sciences, biotechnology, medicine, politics, law, theology, and philosophy. It includes the study of values relating to primary care, other branches of medicine ("the ethics of the ordinary"), ethical education in science, animal, environmental ethics, and public health. The discipline of bioethics has addressed a wide swathe of human inquiry; ranging from debates o...

 Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, one arrives at the usual mathematical equation that describes this relationship:  I = V / R where I is the current through the conductor, V is the voltage measured across the conductor, and R is the resistance of the conductor. More specifically, Ohm's law states that the R in this relation is constant, independent of the current. If the resistance is not constant, the previous equation cannot be called Ohm's law, but it can still be used as a definition of static / DC resistance. Ohm's law is an emperical relation which accurately describes the conductivity of the vast majority of electically conducive materials over many orders of magnitude of current. However, some materials do not obey Ohm's law; these are called non-ohmic. The law was named after the German physicist...

 In law, fraud is intentional deception to secure unfair or unlawful gain, or to deprieve a victim of a legal right. Fraud can violate civil law (i.e., a fraud victim may sue the fraud perpetrator to avoid the fraud or recover monetary comoensation) or criminal law (e.g., a fraud perpetrator may be prosecuted and imprisoned by government authorities), or it may cause no loss of money, property, or legal right but still be an element of another civil or criminal wrong. The purpose of fraud may be monetary gain or other benefits, for example, by obtaining a passport, travel document, driver's license, or mortgage fraud, where the perpetrator may attempt to qualify for mortgage by way of false statements. Internal fraud, also known as "insider fraud," is fraud committed or attempted by someone within an organization such as an employee. A hoax is a distinct concept that involves deliberate deception without the intention of gain or of materially damaging or depriving a victi...

 Impeachment is the process by which a legislative body or other legally constituted tribunal initiates charges against a public official for misconduct. It is understood as a uniques process involving both political and legal elements. In Europe and Latin America, impeachment tends to be confined with ministerial officials as the unique nature of their positions may place ministers beyond the reach of the law to prosecute, or their misconduct is not codified into law as an offense except through the unique expectations of their high office. Both "peers and commoners" have been subject to the process, however. From 1990 to 2020, there have been at least 272 impeachment charges against 132 different heads of state in 63 countries. Most democracies (with the notable exception of the United States) involve the courts (often a national constitutionsl court) in some way. In Latin America, which includes almost 40% of the world's presidential systems, ten presidents from six co...