L3 - Atoms, Molecules, and Ions Flashcards
The basic component of matter cannot be
seen with our eyes - all matter is composed of
invisible atoms which are the fundamental units
of matter.
Atomic Theory
The idea that matter is made up of minute
particles was first conceived by the ancient Greek
philosopher
Democritus
He reasoned that matter consists of
very small particles called “atoms”.
Democritus
The word atom was taken from the
Greek word “?”, meaning
“?”.
atomos, cannot be cut
Postulates of Dalton’s Atomic Theory:
1. All matter is composed of tiny indestructible particles called
atoms.
2. Atoms are indivisible particles which cannot be created or
destroyed in a chemical reaction.
3. Atoms of the same element are identical in mass and properties.
4. Atoms with different element have different mass and
properties.
5. Compounds are formed in small whole numbered ratios such as
1:1 , 1:2, 2:1 and so on.
Postulates of Dalton’s Atomic Theory:
1. All matter is composed of tiny indestructible particles called
atoms.
2. Atoms are indivisible particles which cannot be created or
destroyed in a chemical reaction.
3. Atoms of the same element are identical in mass and properties.
4. Atoms with different element have different mass and
properties.
5. Compounds are formed in small whole numbered ratios such as
1:1 , 1:2, 2:1 and so on.
In any chemical reaction, matter is neither created nor
destroyed.
Law of Conservation of Matter
Also known as the Principle of Matter Conservation, this law
was first proposed by the Greeks with the idea that the
total amount of matter in the universe is constant.
Law of Conservation Of Matter
A chemical compound is always composed of the same
elements combined in constant proportion by weight.
Law of Definite Composition
The Law of Conservation of
Mass/Matter was discovered by
___________ as a fundamental
principle of physics in 1789.
Antoine Lavoisier
Energy is neither created or destroyed
Chemical Energy of Reactants = Chemical Energy of Products
Total Energy of Reactants = Total Energy of Products
Law of Conservation of Energy
This law is also called ______ It was observed by French chemist Joseph
Proust in 1794.
Proust’s Law or Law of Constant
Proportion.
He discovered that
compounds always contained the
same ratio by weight of their elements.
Joseph Proust
When two elements combine to form two or more compounds, the
weight of one element that combines with a fixed weight of the other
are in the ratio of small whole numbers.
Law of Multiple Proportion
is the basic unit
of an element that can be
chemically combined.
Atom
Atom is made up two
regions
Nucleus, electrons
