1. CONCURRENT ENROLLMENT CHEMISTRY
CHAPTER 3
CONCURRENT ENROLLMENT CHEMISTRY

2. Quantum Theory and the Atom
SECTION5.2
Quantum Theory and the Atom
Bohr's Model of the Atom (cont.)
Bohr correctly predicted the frequency lines in hydrogen’s atomic emission spectrum.
The lowest allowable energy state of an atom is called its ground state.
When an atom gains energy, it is in an excited state.

3. Quantum Theory and the Atom
SECTION5.2
Quantum Theory and the Atom
Bohr's Model of the Atom (cont.)
Bohr suggested that an electron moves around the nucleus only in certain allowed circular orbits.

4. Quantum Theory and the Atom
SECTION5.2
Quantum Theory and the Atom
The Quantum Mechanical Model of the Atom (cont.)
Heisenberg showed it is impossible to take any measurement of an object without disturbing it.
The Heisenberg uncertainty principle states that it is fundamentally impossible to know precisely both the velocity and position of a particle at the same time.
The only quantity that can be known is the probability for an electron to occupy a certain region around the nucleus.

5. PERIODIC LAW Periodic law Group Period Blocks
Elements with similar chemical properties occur at regular (periodic) intervals when the elements are arranged in order of increasing atomic numbers.
Group
Period
Blocks
Table can be broken into blocks of elements

6. PERIODIC TABLE

7. ELECTRONIC ARRANGEMENT
Shell (level)
Energy level (where electron is most likely to be found around the nucleus)
Same as period for s and p blocks
One less than period for d block
Two less than period for f block
Subshell (sublevel)
Mathematical model that are the same as blocks, s, p, d, and f (look on page 71)
Orbital
The position of each model in space
s sublevel has only one position
p sublevel has three positions
d sublevel has five positions
f sublevel has seven positions
Spin
Two electrons can occupy the same area, one spinning clock wise and the other spinning counter clockwise

8. Quantum Theory and the Atom
SECTION5.2
Quantum Theory and the Atom
Hydrogen Atomic Orbitals (cont.)
Energy sublevels are contained within the principal energy levels.

9. Quantum Theory and the Atom
SECTION5.2
Quantum Theory and the Atom
Hydrogen Atomic Orbitals (cont.)
Each energy sublevel relates to orbitals of different shape.

10. VALENCE ELECTRONS Look at the periodic table
Each time you fill up the p block of elements in an energy level, you start a new energy level
This means that you can never have more than eight electrons in the outer most energy level at any given time
These electrons are called the valence electrons (electrons found in the valence shell)

11. ELECTRON CONFIGURATION
Hund’s rule
Electrons can not pair until all the orbitals have one electron
Pauli exclusion principle
Only electrons spinning in opposite directions can simultaneously occupy the same orbital

12. ORBITAL NOTATION, SHORT-HAND AND DOT NOTATION
Use arrows to show where the electrons would be
Li, C, As
Do the orbital notation Pb.
Noble gas configuration
Symbol of noble gas above the element you are working with will represent the electron notation up to that point
Li - [He]2s1
C - [He]2s22p2
As - [Ar]4s23d104p3
Dot notation
Use the symbol of an element to represent all electrons except for the valence electrons.
Use dots to represent the valence electrons

13. METALS, NONMETALS AND SEMIMETALS
Transition metals
Inner-transitional elements
Metal properties
As atoms get larger the shielding effect increases, this makes it easier to pull electrons away
Metals do not hold onto electrons, this is why more elements are metals
NONMETALS
Nonmetal properties
SEMIMETALS
Semimetal properties
In a zig-zag formation on the table.
Metals are to the left of the semimetals

14. TRENDS ATOMIC RADIUS IONIZATION ENERGY
As the elements increase in number of protons across a period the attraction of the valence electrons increase
The repulsion or the shielding effect of the inner electrons toward the valence electrons remain the same
This means that the atomic radius decreases as you go across the period
As you go down the group the radius increases
IONIZATION ENERGY
The amount of energy required to remove an electron from an atom
Increases as you go across the period (left to right)
Decreases as you go down the group
There is a slight decrease in energy as you go from one block to the next due to the stability of a filled or half-filled sublevel

15. Periodic Trends Atomic Radius (cont.)
SECTION6.3
Periodic Trends
Atomic Radius (cont.)
For elements that occur as molecules, the atomic radius is half the distance between nuclei of identical atoms.

16. SECTION6.3
Periodic Trends
Atomic Radius (cont.)

17. Periodic Trends
Ionization Energy (cont.)