Atomic StructureAtomic StructureAtoms are made of 3 subatomic particles: Atoms are made of 3 subatomic particles:

proton, neutron, electronproton, neutron, electron

NAME WHERE ELECTRIC SIZE IMPORTANCE FOUND CHARGE

Protons Nucleus Positive (+) 1 amu Determines the identity of an elementNumber of protons is the atomic number

Neutrons Nucleus No Charge 1 amu Determines (w/ protons) the mass of the atom

Electrons Somewhere Negative (-) 1/1836 amu Determines how atoms in the reacts with other

Electron atoms Cloud-exact Each energy level in the

location electron cloud can hold unknown a limited # of electrons

AtomsAtomsAMU = Atomic Mass Unit. It is the size of a AMU = Atomic Mass Unit. It is the size of a

proton. It takes proton. It takes 600,000,000,000,000,000,000,000 protons 600,000,000,000,000,000,000,000 protons to make 1 gram.to make 1 gram.

Atoms are electrically neutral. This is Atoms are electrically neutral. This is because an atom has the same number of because an atom has the same number of protons protons (positive charges) (positive charges) as electrons as electrons (negative charges)(negative charges)

Chemical SymbolChemical Symbol An abbreviation that represents the name of An abbreviation that represents the name of

an elementan element

The chemical symbol can contain 1 or 2 The chemical symbol can contain 1 or 2 letters. The first letter is always capitalized. letters. The first letter is always capitalized. The second letter is lower cased.The second letter is lower cased.

Ex.: Ex.: Hydrogen = HHydrogen = HSilicon - SiSilicon - Si

Atomic NumberAtomic Number

Remember: Make an Remember: Make an A+, you’re #1!A+, you’re #1!

Atomic number is the Atomic number is the number of protons in an number of protons in an element. element. It identifies the It identifies the element.element.

If you change the If you change the number of protons, you number of protons, you change the elementchange the element..

Mass NumberMass Number Mass Number- Equal to the number of protons + the Mass Number- Equal to the number of protons + the

number of neutrons in an atom.number of neutrons in an atom. MASS NUMBER = # PROTONS + # NEUTRONSMASS NUMBER = # PROTONS + # NEUTRONS

We can use the mass number to find the number of We can use the mass number to find the number of neutrons an element has.neutrons an element has.

To find the number of neutrons in an atom, subtract the To find the number of neutrons in an atom, subtract the atomic number from the mass number.atomic number from the mass number.# NEUTRONS = MASS NUMBER - ATOMIC NUMBER# NEUTRONS = MASS NUMBER - ATOMIC NUMBER

Atomic MassAtomic Mass Atomic Mass: The Atomic Mass: The

average mass of all average mass of all known isotopes of an known isotopes of an element. element. This is This is found on the periodic found on the periodic table.table.

Isotopes are the Isotopes are the elements that have elements that have atoms with different atoms with different numbers of neutrons, numbers of neutrons, so a different mass so a different mass numbernumber

IsotopesIsotopes

H2

1

Mass Number

Atomic Number

Chemical Symbol

Ex.: Hydrogen Isotopes

H H H11

21

31

Protium Deuterium Tritium

(Hydrogen-1) (Hydrogen-2) (Hydrogen-3)

IsotopeName

Mass Number

*Because the mass number is different for each isotope of hydrogen, the number of neutrons in each atom is different. The number of protons, however, is the same.

Reading an element tile on the Reading an element tile on the periodic table periodic table

Copy Tile and LabelsCopy Tile and Labels

11

NaSodium

22.990

Atomic Number(Number of Protons & Number of Electrons)

Chemical Symbol

Element Name

Atomic Mass (Average Mass of All Known

Isotopes)

Atoms and APEMANAtoms and APEMAN

APEMAN = A way to remember all parts of an APEMAN = A way to remember all parts of an atomatom

A = Atomic NumberA = Atomic Number

P = ProtonsP = Protons

E = ElectronsE = Electrons

M = Mass NumberM = Mass Number

-A = Atomic Number-A = Atomic Number

N = NeutronsN = Neutrons

Atoms and APEMANAtoms and APEMAN

Example: Example: Sodium-23 Sodium-23

A = Atomic NumberA = Atomic Number 11 11

P = ProtonsP = Protons 11 11

E = ElectronsE = Electrons 11 11

M = Mass NumberM = Mass Number 23 23

-A = Atomic Number-A = Atomic Number -11-11

N = NeutronsN = Neutrons 12 12

Copy and Complete the Table Copy and Complete the Table BelowBelow

Isotope Isotope NameName

Isotope Isotope SymbolSymbol

Atomic Atomic Number Number

Mass Mass NumberNumber

#P#P #N#N #E#E

Iron- 56Iron- 56

1616 1616 1616

KK 3939

Copy and Complete the Table Copy and Complete the Table BelowBelow

Isotope Isotope NameName

Isotope Isotope SymbolSymbol

Atomic Atomic Number Number

Mass Mass NumberNumber

#P#P #N#N #E#E

Iron- 56Iron- 56 5656

FeFe2626

2626 5656 2626 3030 2626

Sulfur- 32Sulfur- 32 3232

SS1616

1616 3232 1616 1616 1616

Potassium- Potassium- 3939

3939

KK1919

1919 3939 1919 2020 1919