Atomic Structure and Electrification Principles

Methods of Electrification

There are three primary electrification methods: by rubbing, by contact, and by induction or influence.

Understanding Coulomb's Law

Coulomb's Law: The attractive or repulsive force exerted between two point electric charges is directly proportional to the product of these charges and inversely proportional to the square of the distance that separates them.

Electric Charge: Protons and Electrons

The Formation of Ions

An ion is an atom that has gained or lost one or more electrons.

Structure of the Nuclear Atom

The central atom has a nucleus in which almost all its mass is concentrated, contributed by the protons and neutrons.

The positive charge of protons is compensated by the negatively charged electrons, which are outside the core. Thus, the atom is electrically neutral.

The nucleus contains, therefore, protons in a number equal to the electrons in the atom.

The electrons spin at high speeds around the nucleus and are separated by a distance.

The Bohr Model

The single electron moves in allowed circular orbits in which it does not emit energy. The electron in each orbit has a certain energy that is greater the further away the orbit is from the nucleus.

The emission of energy occurs when an electron jumps from an initial state of higher energy to another state of lower energy.

Distribution of Electrons

• First layer: 2 electrons
• Second layer: 8 electrons
• Third layer: 18 electrons
• Fourth layer: 32 electrons

Atomic Number and Mass Number

• Z (Atomic Number): The number of protons. It is represented by a subscript before the symbol.
• A (Mass Number): The total number of protons and neutrons.
• N (Number of Neutrons): The mass number minus the atomic number.

Isotopes and Relative Atomic Mass

Isotopes (eLearning Awards website) are atoms of an element that have the same atomic number but different mass numbers.

Relative atomic mass is the mass of an atom measured by comparison with that of a carbon-12 atom.

Radioactivity and Radioisotopes

Radioactivity is the phenomenon by which certain substances emit radiation.

There are three types of radioactive particles: alpha (α) particles, beta (β) particles, and gamma (γ) rays.

The radioisotopes are radioactive isotopes of an element.