Ph 1 Lecture 2 2011

Front 1

Quantum Mechanics

Back 1

1. Energy is not continuos

2. The elementary particles behave like both particles and waves.

3. The movement of these particles are random

Front 2

Quantum Mechanics b

Back 2

4. It is impossible to know the position and the momentum of a particle at the same time. The more accurately we know one aspect, the least we know about the other.

5. The atomic world is nothing like the macroscopic world

Front 3

J.J Thomson

Back 3

First guy to propose a model of an atom and suggested the plum pudding model.

Front 4

Rutherford and Bohr

Back 4

Discovered that certain heavy elements spont. emit alpha particles

Rutherford also said that the atom contained a dense positively charged nucleus and negatively charged electrons were located at some remote point. He also implied that most of the atom was spaced.

Front 5

Rutherford experiment

Back 5

His experiment proved that most of an atom is open space, and the negative electrons were situated at some remote point.

Front 6

Bohr's model

Back 6

Electrostatic forces are balanced with centrifugal forces to keep the electron in balance.

Radiation was not emitted so long as the electron remained in one of its allowed orbits.
As long as electrons stay in their orbits, they don't emit energy.

Front 7

Each shell has

Back 7

2n-1 substates

Front 8

Pauli Exclusion Principle

Back 8

the number of electrons allowed

2n squared where n is the shell number

Front 9

A photon is emitted only when an electron falls from one orbit to another orbit of lower energy

Back 9

An electron in orbit which absorbs energy will be raised to a higher orbit

Front 10

The electron will later release this energy in the form of chacterisitc X-Ray and return to lower orbit

Back 10

The energy of the X-Ray released depends on the binding energy of the electron.

Front 11

What is emitted in the photoelectric effect?

Back 11

Characteristic X-Ray

Front 12

Ionization

Back 12

the process by which a neutral atom acquires a positive or negative charge.

Front 13

Ionizing radiation

Back 13

radiation which is energetic enough to remove an electron of an atom from its orbit.

Front 14

Ionization Potential

Back 14

is the amount of energy required to ionize the least tightly bound electron in an atom. Usually on the order of several electron volts for most elements.

Front 15

Symbol A

Back 15

Atomic mass number = the total number of neutrons and protons

Front 16

Z

Back 16

Atomic number = the number of protons in the nucleus.

Front 17

An atom has the same number of protons

Back 17

and electrons = stability

Front 18

Isotopes

Back 18

Nuclides which have the same number of protons but varying numbers of NEUTRONS. Isotopes have identical chemical properties.

Front 19

Isotones

Back 19

nuclides which have the same number of NEUTRONS

Front 20

Isobars

Back 20

Nuclides which have the same MASS NUMBER (A) BUT DIFFERENT ATOMIC NUMBER Z