Boxes on the Periodic Table

What do they tell us??

Boxes on the Periodic Table

The boxes on the Periodic Table give the following information about an element:

symbol atomic number atomic mass

Symbols

One or two letter abbreviation for an element’s name

Atomic Number (smaller) The number of protons or electrons in an

atom of an element The periodic table is arranged in order of

increasing atomic number

Atomic Mass (bigger)

The average mass of one atom of an element

Measured in atomic mass unit (amu) The protons and neutrons add to make

up the atom’s mass – (the electrons are too small to count)

Calculating Subatomic Particles

Atomic Number = __3_Atomic Mass = _7__

(protons + neutrons)# Protons = _3__

(the atomic number)# Electrons = _3__ (the atomic number)# Neutrons = __4_

(7 – 3)

3

Li

Lithium

6.941

Atomic Number

Element Symbol

Element Name

Atomic Mass

Calculating Subatomic Particles

Element SymbolAtomic Number

Atomic Mass

# proton(atomic number)

# electron

(atomic number)

# neutron(atomic mass – atomic number)

Copper 64 29

Ca 40

19

I have noticed…

Atoms are neutral – same number of protons (+) and electrons (-)

Neutrons are neutral, so they don’t count!

Only 2 of the 3 subatomic particles make up an atom’s mass; the protons and neutrons

And lastly…

If you change the number of protons in an atom you have another element

If you change the number of neutrons in an atom you have an isotope

If you change the number of electrons in an atom you have an ion that is ready for bonding