The Nucleus - (Organic/Nuclear Chemistry)

Nucleons

Atomic nuclei are made of protons and neutrons

Nuclide

An atom, identified by the number of protons and neutrons in its nucleus

Superscript

The mass number

Subscript

The atomic number

The mass number in

228

The atomic number in

88

Mass defect

The difference between the mass of an atom and the sum of the masses of its particles

Nuclear binding energy

The energy released when a nucleus is formed from nucleons

E = mc²

Mass can be converted to energy, and energy to mass

Mass defect cause

Caused by the conversion of mass to energy upon formation of the nucleus

Binding energy per nucleon

The binding energy of the nucleus divided by its number of nucleons

Binding energy per nucleons usage

To compare the stability of different nuclides

The higher the binding energy per nucleon,

The more tightly the nucleons are held together

Greatest binding energies per nucleon (most stable)

Elements with intermediate atomic masses

Band of stability

The stable nuclei cluster over a range of neutron-proton ratios

As the number of protons increases,

The ration increases from 1:1 to 1.5:1

Stable nuclei

René to have even numbers of nucleons

The stability of a nucleus is greatest when,

The nucleons (like electrons) are paired

The most stable nuclides

Those having 2, 8, 20, 28, 50, 82, or 126 protons, neutrons, or total nucleons

Nuclear shell model

Nucleons exist in different energy levels, or shells, in the nucleus

Magic numbers

The number of nucleons that represent completed nuclear energy levels (2, 8, 20, 28, 50, 82, and 126

The nuclear shell model suggests

That there might be an ‘island of stability’ for elements that lie beyond uranium in the periodic table

Nuclear reaction

A reaction that affects the nucleus of an atom

The total of the atomic numbers and the total of the mass numbers

Just be equal on both sides of the equation

Transmutation

A change in the identity of a nucleus as a result of a change in the number of its protons