What do atoms look like??? Draw what you think an atom would look like if it were as big as a baseball.

How big do you think an atom is?? How much bigger is a baseball than an atom?

Atomic Structure Movie

ATOMIC STRUCTURE

What happens when the # of particles changes?

ATOMIC STRUCTURE TOOL

Experiment animation

How do you Build an Atom ?

GO TO PHET….

 Isotopes are forms of the same atom that vary in mass. 

There are two different types (isotopes) of copper atoms. One type of copper atoms weighs in at 62.93 amu, the other has a mass of 64.94 amu. The lighter isotope is more common with  69.09% of the naturally occurring copper having a mass of 62.93 amu per atom. The remainder of the atoms, 30.91 %, have a mass of 64.94 amu.

To find the AVERAGE ATOMIC MASS of an atom, we take into account all of the isotopes that exist and the percentage of each type. The calculation of the average atomic mass is a WEIGHTED AVERAGE.

 Average atomic mass = Σ (mass of isotope × relative

abundance)

AVERAGE ATOMIC MASS: ISOTOPES

Since there are two isotopes, so we will be adding the contributions of 2 isotopes. (That’s where the Σ sign comes in. ) The relative abundance is simply the percentage of the isotope, but in decimal format.  0.90% corresponds to a relative abundance of 0.6090.

Average atomic mass of copper = (62.93 amu × 0.6909) + (64.94 amu × 0.3091)= 63.55

What’s the remaining percentage? ______________

What the average mass of silver? _______________

FIND THE AVERAGE MASS OF SILVER

Look over the data before you begin the problem. Estimate the value of the answer before you begin the calculation. Will the weighted average be closer to 28,  29, or 30?  

Calculate the average… How good was your guess?

FIND THE AVERAGE MASS OF SILICON..

Make a Guess…. What do you think the answer is? _________

Now, do the calculation– the average mass is ________

FIND THE AVERAGE MASS OF IRON

Atomic Mass IsotopeFormula MassMolar MassMass NumberProtonNeutronElectronAverage Atomic Mass

SOME VOCAB TO REVIEW

ELECTRON ORBITALS AND THE PERIODIC TABLE– LET’S COLOR CODE OURS.

Bohr’s model and electrons absorbing energy

ABSORPTION SPECTRUM

The Principal Energy Level (the #) only holds that # of sublevels.

ELECTRON CONFIGURATIONS

NUMBER OF ELECTRONS PER SUBLEVEL

OVERLAP OF ENERGY LEVELS

Let’s try a few….

Li = 1s22s1

Boron =

WRITING ELECTRON CONFIGURATIONS

Kernal- Represented by the symbol. It is the nucleus and the inner electrons of an atom or ion

Valence Electrons- Represented by the dots. The electrons in the outer most energy level of an atom or ion.

LEWIS DOT STRUCTURES

Show the valence Electrons—the ones that make bonds

Oxygen gets 6 dots.

Chlorine gets 7 dots.

NOTE****There is an order we fill the dots.

LEWIS DOT DIAGRAMS:

What do you think the Lewis Dot Diagram will be for these Elements? Write the Dot Diagram for each

NaBeAlCNOClNeWhat do you notice about the Dot Diagram series you

just made? What do you notice about the position of the elements on the periodic table?

PRACTICE THIS

LDDs for Ions:What’s the charge for Oxide? How did it get that

charge?

What’s the charge for Aluminum (when it’s ionic)? What happened to the atom that it now has a charge?

What do you notice about the valence shell of these ions?

WHAT HAPPENS WHEN THERE’S A DIFFERENT # OF ELECTRONS