Atom and its functions, Lecture notes of Anatomy

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Centuries of Discovery of

Atom

The Greek Atom

• (^) 400 B.C. - Democritus thought matter could not be divided indefinitely.

Dalton Atom

• (^) In 1808, John Dalton, an English school teacher, published a book summarizing his experiments, which showed that elements could be classified according to integral value of atomic mass.
• (^) an element was composed of identical atoms, each reacting the same way in chemical reaction.

Example:

• (^) All oxygen atoms were alike. They looked-alike, they were constructed alike and they reacted alike.

Mendeleev’s Periodic Table of

Elements

Elements of Interest in Radiology

Thomson Atom

• (^) In the late 1890’s while investigating the physical properties of cathode rays, J.J. Thomson concluded that electrons were integral part of all atoms
• (^) He describe that atom as looking something like a PLUM PUDDING.

Ernest Rutherford

• (^) He disproved Thomson’s model of the atom in 1911.
• (^) He introduced the nuclear model, which contains a small, dense, positively charge center surrounded by a negative cloud of electrons.
• (^) He called the center of the atom the nucleus.

ATOMIC

STRUCTURE

• The universe is

composed of

matter

• All matter is

found to consist of

simple substances

• elements
• Elements are

usually chemically

linked to other

Matter is

anything that

has mass and

volume

ATOMIC STRUCTURE

ATOM

Fundamental building blocks of matter Smallest particle of an element Neutral charged

Atomic Structure

• (^) The Atom is essentially empty space.
• (^) The nucleus of an atomic contains most of its mass.
• (^) The possible electron orbits are grouped into different “shells”.
• (^) The number of protons determine the chemical element

Fundamental Particles

1. Proton
2. Neutron
3. Electron