Chemical Reactions 

Property: Something that can be observed about a substance

Melting Point: The temperature at which a solid will begin to melt and turn into a liquid 

Boiling Point: The temperature at which the liquid will begin to boil and turn into a vapor.

Physical Property: Things about a substance which you can use your senses to gain information.

Chemical Property: any of a material's properties that becomes evident during, or after, a chemical reaction

Atoms: The tiny pieces that all matter- all the stuff in the world- is made of  

Substance: Something that is made of all the same atoms or groups of atoms

Chemical Formula: a representation of a substance using symbols for its constituent elements. 

Molecules: A group of atoms joined together in a particular way   

Chemical Property: characteristic of a particular substance that can be observed in a chemical reaction. 

Scale: The relative size of things

Macroscale: When seen with the naked eye, don’t need a microscope

Microscale/Atomic Scale: Can be seen only with a microscope

Chemical Reaction: A process in which atoms rearrange to form new substances

Rearrange: To change the order or position of something

Atomic Number: the number of protons in the nucleus of an atom

Atomic Mass: the mass of an atom expressed in atomic mass units

Isotope: an atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons 

Proton: a subatomic particle that has a positive charge and that is found in the nucleus of an atom.

Neutron: a subatomic particle that has no charge and that is found in the nucleus of an atom.

Electron: negatively charged particles found in electron clouds outside the nucleus. The size of the electron clouds determines the size of the atom.

Chemical Bond: an interaction that holds atoms or ions together

Valence Electron: an electron that is found in the outermost shell of an atom and that determines the atom's chemical properties

Ions: a charged particle 

Ionic Bond: a bond that forms when electrons are transferred from one atom to another, which results in a positive ion and a negative ion.

Covalent Bond: a bond formed when atoms share one or more pairs of electrons

reactant: A starting substance that is part of a chemical reaction

Product: An ending substance that is made during a chemical reaction

    1. Different substances have both different physical and chemical properties.

    2. Things that are too small (or too large) to see can be studied with models

    3. Substances have different properties because they're made of different groups of atoms. These groups vary in type or number of atoms that make up the group.

    4. Groups of atoms repeat to make up a substance

    5. During a chemical reaction one or more starting substances (reactants) change into one or more different substances (products)

    6. During a chemical reaction, atoms do not change from one type to another

    7. During a chemical reaction, atoms rearrange to form different groups of atoms

    8. During a chemical reaction, all of the atoms that make up the reactants rearrange to form the products