The Periodic Table
There are 118 of these on the periodic table
Elements
A pure substance with only one type of atom
element
Physical change
These are what we start with in a chemical equation, found on the left side
reactants
How many carbon atoms are in the molecule C6H12O6?
6 carbon atoms
The number located below the chemical symbol
Mass number
Two or more atoms chemically bonded together
Molecule
A change in a substance that changes what the substance is
Products
In this equation what are the reactants?
2Ca+O2 ---> 2CaO
2Ca + O2
atomic number
Two or more different kinds of atoms chemically bonded together
compound
Color, density, and melting point are all examples of these kinds of propeties
Physical properties
This number cannot be changed and indicates how many atoms of each element are present
subscript
In a chemical reaction if the products get hotter than the reactants what kind of reaction happened?
exothermic
The atomic number tells us how many positive protons are in an atom. What else does it tell us about that atom?
The number of electrons
a combination of elements and compounds that can be separated through physical means (i.e. salt water)
Mixture
Flammability, toxicity, and acidity are all examples of these kinds of properties
chemical properties
This number can be changed in a chemical equation to balance it and tells us how many molecules of a substance we have.
coefficent
What is the equation for density?
density= Mass/Volume
The elements on the table are ordered using this number
The atomic number
compound
Physical change
These cannot be created or destroyed during a chemical reaction. There must be the same number of these on each side of a chemical equation.
atoms
Is this equation balanced?
N2 + 3H2 -----> 2NH3
Yes it is balanced