A chemical element can come in different varieties
Isotopes
Are different because they contain different numbers of protons
Elements
Of an element is the number of protons in the nucleus of an atom of that element
Atomic number
The total number of protons and neutrons in an atom is
Mass number
Are atoms that have the same number of protons but different numbers of neutrons
Isotopes
Are the only thing that will change
Neutrons
Is defined as one twelfth of the mass of a carbon-12 atom
Atomic mass unit
Of an element is a weighted average mass of the atoms in a naturally occurring sample of the element
Atomic mass
Reflects both the mass and the relative abundance of the isotopes as the occur in nature
A weighted average mass
is an arrangement of elements in which the elements are separated into groups based on a set of repeating properties
Periodic table
Allows you to easily compare the properties of one element to another element.
A periodic table
Each horizontal row of the periodic table is called a
Period
Each vertical column of the periodic table is called a
Group or family
Isotopes of an element have
the same number of protons but different numbers of neutrons