Atom Flashcards
Anything that takes up space and has mass
Matter
Quantity of matter in a body regardless of its volume or any forces acting on it
Mass
Measure of the force of gravity acting on it
Weight
Building blocks of matter
Atoms
Particles much smaller than atoms
Subatomic particles
How many elements have been identified ?
112
Naturally-occuring elements
92
Artificially - produced elements
20
He named the smallest piece of matter “atomos”
Democritus
Meaning “not to be cut” / indivisible
Atomos
They favored the earth, fire , air and water to the nature of matter
Aristotle and Plato
Laid the foundation for modern atomic theory
John Dalton (1808)
Atoms can’t be subdivided , created or destroyed
Modern Atomic Theory
Formed by joining of atoms of two or more elements
Compounds
Dalton’s atom had _________ to account for chemical combination
Hooks and eyes
Atoms of different elements combine in simple whole number ratios to form chemical compounds
Law of multiple proportions
He is concerned with the investigations of the electrons ( cathode rays)
Joseph John “J J” Thompson
Concluded that “electrons were an integral part of all atoms”
JJ Thompson
Thomson proposed a model of the atom that is called
Plum Pudding
Negatively charged that is also known as electrons
Corpuscles
Introduced the nuclear model of the atom
Discovered the nucleus
Ernest Rutherford
Proposed the planetary model
Niels Bohr
He proposed the wave-particle duality
Louis de Broglie
All particles of matter moving at some velocity would have the properties of a wave
Particle- Wave Duality
He created the quantum mechanical model of the atom
Erwin Schrodinger
The probability of finding the electron is the greatest
The cloud is most dense
Nucleus is sorrounded by an electron cloud
This model intoduced the concept of sub- energy levels
Quantum mechanical model
Electrons do not move about an atoms in a definite path like the planets around the sun
Wave mechanics theory
Atom has small positively charged nucleus surrounded by a large region where there are electrons (negative ) to make the atom neutral
Modern Atomic atomic model