HELLO MINIONS…Now for the nifty stuff

HISTORY LESSON…

• 430 BC (a long, long time ago…)

• Greek Philosopher• Democritus

• Matter is formed by small pieces that could not be cut into smaller parts.

• ATOMOS – Uncuttable• ATOM

HISTORY LESSON CONTINUED…

• Jump forward to the 1600’s• John Dalton (English chemist)

• Came up with some ideas• All elements are composed of

atoms that cannot be divided• Atoms of same element are

alike and have the same mass• Different elements are different

and have different masses• Atoms cannot be changed into

another atom• Atoms cannot be created or

destroyed, only rearranged• Every compound is made of

atoms of different elements in set ratios

MORE HISTORY…

• 1897 (English scientist) J.J. Thompson• Came up with a theory of

the atom being a positive ball with scattered negative charges surrounding it.• Negative charges later

became known as “Electrons”

STILL MORE HISTORY…

• 1911 Ernest Rutherford (Thomson’s student)• Gold foil experiment

• Nucleus• Protons

LAST BIT OF HISTORY…

• 1920’s• Scientists said a cloud

surrounds the nucleus• Not like planets

orbiting a sun• Electron’s movement is

related to the “energy level” (or specific amount of energy it has)

PARTICLE CHARGES

COMPARISON OF PARTICLES

• Protons and Neutrons are about the same mass • (neutrons are a

weeeeeee bit bigger, but not much)

• Electrons match Protons charge for charge• But…

• Electrons are the size of a Proton!!!

WE’RE NUMBER…

• Every atom of an element has the same number of protons

• Carbon has 6 protons

• Oxygen has 8 protons

• Iron has 26 protons• Radium has 88

protons!!!

• This unique number of protons in the nucleus of an atom is an element’s ATOMIC NUMBER!

THERE IS ALWAYS AN EXCEPTION…

• Although all atoms have the same number of protons…

• The number of Neutrons can differ!• When the number of neutrons differ from the protons,

this is called an ISOTOPE.

THERE IS ALWAYS AN EXCEPTION…

• An isotope is identified by its “MASS NUMBER” which is the sum of its protons and neutrons.• For example …

• Carbon-12 (most common) (6 protons + 6 neutrons)• Carbon-13 (6 protons + 7 neutrons)• Carbon-14 (6 protons + 8 neutrons)

OH!

Questions!!!!