Chem+Basics

media type="custom" key="823203" **Chemistry oF Life**

Atoms Atom is a greek word that means " Un-able to Cut."  **Nucleus**- Center of the atom; combination of nuetrons and protons.  **Element**- is a pure substance that consists entirely of only one type of atom. More than 100 elements are known. E.g H ** Radioactive Isotopes ** - Some isotopes are radioactive, meaning their nuclei are unstable and break down at a constant rate over time. ** Ions- ** An atom that loses electrons has a positive charge. An atom that gains an electron has a negative charge. These positively and negatively charged atoms are called Ions. **Solutions **- When ions gradually disperse in the water, forming a type of mixture called a solution. All the compounds of a solution are evenly distributed throughout the solution.
 * Electron**- negativly charged particle ( - ) with 1/1840 the mass of a proton.
 * Protons**- P for positivly charged particle ( + )
 * Neutrons**- N for neutral carry no charge
 * Isotope**- Atoms of the same element that differ in the number of neutrons they contain are known as Isotopes.
 *  Chemical Compounds ** - A compound formed by 2 or more elements forming together in definite proportion.
 * Chemical Bonds**- The atoms in compounds are held together by chemical bonds.
 * Ionic Bond- **is formed when one or more electrons are transferred from one atom to another .
 *  Covalent Bond ** - A covalent bond is formed when the electrons of atoms are shared.
 * Polarity**- A molecule in which the charges are unevenly distributed is called a polar molecule, because the molecule is like a magnet with poles.
 * Hydrogen Bonds**- Hydrogen bonds are not as strong as ionic, or covalent bonds, but their ability to form so many bonds is the reason they form multiple bonds for the water.
 *  Cohesion ** - An attraction between molecules of the same substance: because of hydrogen bonding water is extremely cohesive.
 * Solutions and Suspensions**
 *  Suspensions-  ** Some molecules do not dissolve of disperse thorough out the water, and just float and stay at the top, these are called suspensions.