Module 5: Atoms and Its Sub-atomic Particles

Atoms

The idea that matter is made up of very small particles called _____.

Atomos

Uncuttable o indivisible

Democritus

• The idea that matter is made up of very small particles called atoms

• Believed that there were many kinds of atoms as there were kinds of substances

Atomic Theory

In 1804, the ______ was fully developed by John Dalton, and English school master and accepted by chemist and physicist.

John Dalton

He developed the Atomic Theory in 1804

Dalton’s Atomic Theory

Atoms are composed tiny indivisible particles

Modern Atomic Theory

Atoms are complex and are divisible

Dalton’s Atomic theory

Atoms of a given substance are identical

Modern Atomic theory

Not all atoms of the same elements are alike

Dalton’s Atomic Theory

Atoms are permanent and cannot be decomposed

Modern Atomic Theory

Atoms can be distinguished by radiations

Protons, Electrons, Neutrons

Give the three sub-atomic particles

Henry Becquerel, Ernest Rutherford, Pierre Currie, Julius Plucker

Discoveries by _______, ______, ______, ______ and others and the results of many experiments led to the determination of the three sub-atomic particles of atoms called electron, proton and neutron.

Electron (e-)

negatively charge particle

Proton (p+)

is a positively charge particle

Neutron (n)

is a no charge particle

Center of the atom/Nucleus

The protons and neutrons are found at the _______

Nucleus

The center of the atom is called

Electrons

are found outside the nucleus in shells or energy levels.

Atomic number

The number of protons in the nucleus is defined as the ________

Atomic weight

The ____ is the sum of the number of protons and neutrons in the nucleus. (protons + neurons)

Equal

The number of electrons in the electron cloud of an atom is _____ to the number of protons in the nucleus.

Neutral

The number of electrons in the electron cloud of an atom is equal to the number of protons in the nucleus. Hence, the atom is _____.