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Chemistry Terms, Definitions and Vocabulary Words

 
Anion
A negatively charged ion.


Atomic Mass
The mass of a single atom in terms of its subatomic particles such as electrons, protons and neutrons.


Cation
A positively charged ion.


Covalent compounds
Covalent compounds involve the sharing of electrons between atoms. An electron pair in one atom might contain an electron from another pair in another atom. There is no transfer of electrons from one atom to another.


Electronegativity
The ability of an atom to attract electrons.


Electrons
Subatomic particles that exist around the nucleus of an atom and carry a negative charge. They have a much smaller mass than the proton.


Ionic compounds
Ionic compounds are the result of cations and anions combining. They are formed from the ionic bond between atoms. This bond results from a high difference in electronegativity between atoms. There is a transfer of electrons from atom which are added to the other atom.

In other words the atom with the highest electronegativity from the right side of the periodic table takes the electrons away from the atoms with the lowest electronegativity on the left side of the periodic table. For example, the combination of elements from Group I with those of Group 17 on the periodic table usually leads to ionic compounds.


Ionization energy
The amount of energy needed to remove an electron from an atom’s highest energy level or shell.


Molar Mass
The mass of one mole of a substance. The substance can be composed of atoms or molecules.


Mole
The amount of a substance that contains 6.02 x 1023 atoms, molecules or particles. Its weight in grams corresponds to its atomic mass.


Neutrons
Subatomic particles that exist inside the nucleus of an atom along with protons. The simplest form of hydrogen does not contain neutrons in its nucleus but its isotopes do.


Protons
Positively charged particles that exist in the nucleus of an atom along with neutrons in most cases.





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