Atomic Models, Quantum Theory, and the Periodic Table
Thomson Model of the Atom
In the Thomson model, electrons (e-) are embedded in a sphere of uniform positive charge, like plums in a pudding. There is no distinct nucleus.
Rutherford’s Nuclear Model
The Rutherford model proposes a nucleus that is very small in comparison with the volume of the atom. This nucleus contains almost the entire mass of the atom and all of its positive charge. Electrons form a “crust” (electron cloud) spinning around the nucleus and are relatively far from it.
The Neutron:
Read MoreChemical Nomenclature: Naming Inorganic Compounds
Binary Salts: Definition and Nomenclature
Binary salts are inorganic compounds composed of two different elements, typically a metal and a nonmetal. When the nonmetal is a halogen, these compounds are specifically called halides. They can be considered the result of replacing the hydrogen (H) in a hydracid with a metal.
This general reaction illustrates their formation:
Acid + Base → Salt + Water (H2O)
In this context, the acid is typically a hydracid, the base is a hydroxide, and the resulting compound
Read MoreNanomaterial Fabrication, Imaging, and Drug Delivery Applications
Chemical Vapor Deposition (CVD) Fundamentals
Chemical vapor deposition (CVD), a hybrid method using chemicals in the vapor phase, is conventionally used to obtain coatings of a variety of inorganic or organic materials. It is widely used in industry because of relatively simple instrumentation, ease of processing, the possibility of depositing different types of materials, and economical viability. Under certain deposition conditions, nanocrystalline films or single crystalline films are possible.
Read MoreColor’s Impact on Heat Absorption: Black vs. White Surfaces
Understanding Heat Absorption by Color
The color of an object plays a crucial role in determining its ability to absorb heat, based on the principles of heat transfer, particularly radiation. Heat lamps emit electromagnetic waves, which transfer energy when they strike an object. The amount of energy absorbed depends significantly on the object’s color and surface properties.
Black Surfaces: Efficient Heat Absorbers
Black surfaces are highly efficient absorbers of radiant energy because they absorb
Read MoreUnderstanding Phase Changes in Physics: Key Concepts Explained
Quan una substància passa d’un estat a un altre, en física es diu que canvia d’estat.
SOLID -> (fusió) LIQUID -> (vaporització) GASOS
<- (solidificació) <- (condensació o gel)
Sublimació ————– ——————>
Crystallització ——-
Lleis de la solidificació:
a) Una substància és pura quan es fon, ho fa a una temperatura anomenada temperatura de fusió.
b) La temperatura de fusió es manté constant mentre la substància es solidifica.
c) Els líquids purs
Fundamental Building Blocks of Life: Elements and Molecules
Components of Living Matter
Composition of Matter
Matter consists of atoms.
Key Definitions
- An atom is formed by small particles.
- Elements are substances that consist of a single type of atom. There are 92 naturally occurring elements.
- Substances are mostly chemical compounds.
Chemical Components: Sources and Examples
Chemical components are unions of different atoms. They originate from:
- Rocks and minerals (inorganic world): For example, marble is calcium carbonate, and gypsum is calcium sulfate. Calcium