Atomic Models: Rutherford to Quantum Mechanics
Rutherford Model
The atom has a small, central nucleus with a positive electric charge, containing nearly all of the atom’s mass. Electrons with negative electric charge orbit the nucleus in long-distance circular paths. The electrical attraction between electrons and the nucleus provides the centripetal force for this revolution. The sum of the negative charges of the electrons equals the positive charge of the nucleus, making the atom electrically neutral.
Bohr Atomic Model
Postulate 1: Electrons
Read MoreBiochemistry and Biophysics: Fundamentals of Life’s Chemistry
Biochemistry and Biophysics: The Chemistry of Life
Biochemistry and biophysics are the sciences that deal with the basic chemistry of life. The objective is to study the chemical composition of living beings, the relationships between their chemical compounds, their transformations, regulation, and how these transformations have repercussions in the field of physiology of organisms.
Bioelements and Biomolecules
Bioelements are distinguished as primary, secondary, and trace. They combine to form organic
Read MoreLearn Spanish: Numbers, Questions, and Pronouns
Numbers in Spanish
- One – Uno
- Two – Dos
- Three – Tres
- Four – Cuatro
- Five – Cinco
- Six – Seis
- Seven – Siete
- Eight – Ocho
- Nine – Nueve
- Ten – Diez
- Eleven – Once
- Twelve – Doce
- Thirteen – Trece
- Fourteen – Catorce
- Fifteen – Quince
- Sixteen – Dieciséis
- Seventeen – Diecisiete
- Eighteen – Dieciocho
- Nineteen – Diecinueve
- Twenty – Veinte
- Twenty-one – Veintiuno
- Twenty-two – Veintidós
- Twenty-three – Veintitrés
- Twenty-four – Veinticuatro
- Twenty-five – Veinticinco
- Twenty-six – Veintiséis
- Twenty-seven – Veintisiete
- Twenty-eight – Veintiocho
- Twenty-
Side Chain Effects on Polymer Properties
Effect of Side Chains on Polymer Properties
Hydrogen as a Side Chain
In hydrogen polymers, the properties are determined by C-H bonds. Thus, these polymers are:
- Water-resistant
- Soluble in organic solvents
- Resistant to chemical attack
- Sensitive to free radical attack
Hydrogen as a side group does not provide any steric hindrance to the torsional mobility of the main chain. Therefore, such polymers have low glass transition temperatures. The small size of hydrogen favors the packing of chains; hence, the
Read MorePetroleum, Metallurgy, and Chemical Products: Uses and Impacts
Petroleum: Formation and Uses
Oil is a mixture of hydrogen and carbon (hydrocarbons) formed by the decomposition of the remains of marine animals and plants that were buried at the bottom of the sea, subjected to elevated temperatures and the action of bacteria for millions of years. It is a dark brown, oily liquid with a characteristic odor.
Fractions Obtained by Distillation:
- Refinery gas: Similar in composition to natural gas.
- Petrol: Used as a solvent and as fuel in spark-ignition engines.
- Kerosene:
Atomic Models and Chemical Bonding: A Comprehensive View
Atomic Models
Dalton Model
- Each element is composed of indivisible particles called atoms.
- In an element, all the atoms are identical.
- Atoms of different elements are all different.
- When atoms of more than one element combine, they form molecules. Compounds are made of molecules.
- In a chemical reaction, atoms are not created, destroyed, or changed into other types of atoms.
Thomson Model
Thomson based this model on his work with cathode rays. In this model, an atom consists of a positively charged jellylike
Read More