1. Periodicity & Nuclear Chemistry

2. The Periodic Table

3. Dimtri Mendeleev Father of the Periodic Table
His first Periodic Table was compiled on the basis of arranging elements in ascending order of atomic mass and grouping them by similarity of properties.  

4. Advantages
Mendeleev predicted the discovery of other elements and left space for these new elements, eka-silicon (germanium), eka-aluminium (gallium), and eka-boron (scandium). Thus, there was no disturbance in the periodic table.
He pointed out that some of the then current atomic weights were incorrect.
He provided for variance from atomic weight order.
Disadvantages
There was no place for the isotopes of the various elements.
His table did not include any of the noble gases, which hadn't been discovered.

5. Henry Mosley
In 1914, Henry Moseley found a relationship between an element's X-ray wavelength and its atomic number and therefore resequenced the periodic table.
Ever since, elements have been arranged on the periodic table according to their atomic numbers. The structure of the table reflects the particular arrangement of the electrons in each type of atom.

6. Regions on the P - Table Metals -most are solid at room temperature
Metalloids
-elements that are next to the stair step line
-have properties of both metals and nonmetals
- semiconductors
Transition metals (sub group)
-elements in groups 3-12
-they are metals
-have properties not found in elements of other groups
Example: Iron, cobalt and nickel are the only substances known to be magnetic
Metals
-most are solid at room temperature
-most are shiny
-most are good conductors of heat and electricity
Non-metals
-most are brittle and dull
-most are not good conductors of heat and electricity - insulators

7. VIDEO!!
&q=Alkali+Metals

8. A group is a vertical column in the periodic table of the elements.
Groups are considered the most important method of classifying the elements. In some groups, the elements have very similar properties and exhibit a clear trend in properties down the group — alkali metals, alkaline earth metals, halogens and noble gases.
A period is a horizontal row in the periodic table of the elements.
Elements in the same period have the same number of occupied energy levels. (i.e. Bohr’s electron orbitals)

9. Periodic Trends
Atomic Mass increases as you go across a period and down a group, but there are exceptions. (Ar & K)
Chemical Reactivity for Metals increases as you go down a group, and to the left, example Alkali metal video, heaviest = most reactive
Chemical Reactivity for Nonmetals decreases as you go down a group and increases as you go across the periods and to the right, this excludes “Noble Gases”
lighter = more reactive

10. Metal Reactivity

11. Nuclear Change

12. What happens if the energy released & absorbed from a particle is not the same?
Fluorescence is a property of some molecules in which light of one colour is absorbed that results in light of a different colour being emitted.
Energy is lost in two stages - small amounts are lost first, then a large amount, resulting in the emission of a photon of light.
The energy of the emitted photon is smaller than the absorbed photon because the energy is related to the wavelength.
There is a difference in the colour light that is absorbed to that which is emitted. Thus, fluorophores that absorb blue light (short wavelength - high energy) usually emit green fluorescent light (longer wavelength - lower energy)

14. Radioactivity
Radioactivity is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves.
This is a random process on the atomic level, in that it is impossible to predict when a given atom will decay, but given a large number of similar atoms, the decay rate, on average, is predictable.

15. Pierre & Marie Curie
They studied radioactive materials, particularly pitchblende, the complex mineral from which uranium was extracted.
After some time they also determined that pitchblende must contain traces of an unknown substance far more radioactive than uranium.
In July 1898, Pierre and Marie together published an article announcing the existence of an element which they named "polonium," in honor of her native Poland.

16. Radioactive Half-life
The radioactive half-life for a given radioisotope is the time for half the radioactive nuclei in any sample to undergo radioactive decay.
After two half-lives, there will be one fourth the original sample, after three half-lives one eight the original sample, and so forth.

17. Radioactive Half-life Cont.

18. Half-life Animation

19. Half-life Calculations
A = x Ao
A = Final Amount, Ao = Initial Amount
x = half – lives
t = x
T1/2
t= time, T1/2 = Half – life, x = half-lives

20. Half-life Example
The Half-life of Lithium – 9 is 1.3 minutes. How much Lithium – 9 will remain after 6 minutes, if the original sample contained 8 grams of radioactive Lithium – 9?

21. Radioactive Decay
Radioactivity refers to the particles which are emitted from nuclei as a result of nuclear instability.
The most common types of radiation are called alpha, beta, and gamma radiation, but there are several other varieties of radioactive decay.

22. Alpha (α) Decay:
The reason alpha decay occurs is because the nucleus has too many protons which cause excessive repulsion.
In an attempt to reduce the repulsion, a Helium nucleus is emitted. The way it works is that the Helium nuclei are in constant collision with the walls of the nucleus and because of its energy and mass, there exists a nonzero probability of transmission.

23. Alpha Decay Cont.
That is, an alpha particle (Helium nucleus) will tunnel out of the nucleus. Here is an example of alpha emission with americium-241:

24. Beta (ß) Decay
Beta decay occurs when the neutron to proton ratio is too great in the nucleus and causes instability. In basic beta decay, a neutron is turned into a proton and an electron. The electron is then emitted.

25. Beta Decay Cont.
Here's a diagram of beta decay with hydrogen-3:

26. Gamma Decay
Gamma decay occurs because the nucleus is at too high an energy. The nucleus falls down to a lower energy state and, in the process, emits a high energy photon known as a gamma particle.

27. Gamma Decay Cont.
Gamma ray emission usually occurs with alpha and ß emission. Gamma rays have no charge or mass, so their emission doesn't change the chemical composition of the atom. Instead, it results in a loss of radiant energy. Gamma ray emission occurs because the nucleus is often unstable after alpha and ß decay.

28. Gamma Decay Cont.
Here's a diagram of gamma decay with helium-3:

29. Nuclear Equations
Determining Nuclear Change to Mass number and atomic number
Beta particles, 0-1e, mass number does not change, increase atomic number by 1
Alpha particles, 42He, decreases mass number by 4 and atomic number by 2
Gamma emission, results in a lose of a photon, 10n, increasing mass number by 1,