An atom is made up of 3 subatomic particles

• Sum of the protons (atomic number) and neutrons

• Atoms with the same number of protons and different number of neutrons are isotopes

Mass Number

• The number of protons

• Tells you the identity of the atom (found in upper left corner of periodic table)

Atomic Number

How atoms differ

Isotope Notation

Isotope Notation gives a summary of a specific isotope.

Mass Number

Atomic Number

Charge

Symbol

• Has more protons than electrons

• Called a CATION

Positively Charged

• Has more electrons than protons

• Called an ANION

Negatively Charge

Negative vs Positive vs Neutral

Hyphen Notation

The full name or symbol of the element - the mass number

Periodic Table

Information given on table:

• Found on the periodic table

• Is an AVERAGE of the mass number of multiple isotopes (will discuss later)

Atomic Weight

• Refers to ONE specific isotope

• Get by adding protons and neutrons (NOT found on periodic table)

Mass Number

Mass Number vs Atomic Weight

Isotope Charts

Fill in the blanks using the information provided. Good way to practice counting protons, neutrons, and electrons.