MODULE 2 - ATOM Flashcards
What does Democritus said?
Atom was fundamental, indestructible, indivisible particle.
is an incredibly small but smooth and whole object
atom
universe seemed to be both
changing and constant
were two of the most important theorists about the natural and physical world.
Leucippus and Democritus
Leucippus and Democritus are called _____ in Ancient Greece
physicists
_____ idea that things are made up of much smaller things that cannot be changed nor divided. Suggested by Leucippus and Democritus
atomism
where there are no atoms, there is a
void
Atoms are incredibly small and cannot be divided, hence atomos
uncuttable
Atoms themselves are
solid, homogeneous and cannot change
Atoms _____ in the void cause the changes we see in our universe.
moving about and colliding
Greek philosophers
THALES (640- 540BC)
ANAXIMENES (611-546BC)
HERACLITUS (540-475BC)
EMPEDOCLES (430-390BC)
thought that the basic element of matter was WATER
THALES (640- 540BC)
on the other hand, thought it was Air
ANAXIMENES (611-546BC)
thought FIRE was the basic element.
HERACLITUS (540-475BC)
combined these ideas and added a fourth element, EARTH.
EMPEDOCLES (430-390BC)
Mesopotamians:
- techniques to utilize metals like gold and copper.
- assigned certain symbols to match metals with the heavenly bodies such as the Sun and Moon.
Egyptians
adapted techniques from the Mesopotamians and perfected the use of bronze, dye and glass that the Greeks later copied.
Chinese
also had their own processes for metalwork and ceramic materials, but they especially focused on finding minerals, plants and substances that could prolong life
Indians
had a kind of alchemy (rasayana) that looked at different substances and practices for Vedic medicine.
Arabs and Muslims
enriched not only the practice but also the literature of chemistry. In particular, the scholar Jabir Ibn-Hayyan, also known as Geber, translated the practices and Aristotelian thinking of the Greeks and wrote extensively on how metals can be purified. He came up with the preparation of acids such as nitric, hydrochloric and sulfuric acids, as well as aqua regia (nitro-hydrochloric acid).
Robert Boyle
- rejected a concept proposed by the alchemists notably Paracelsus that matter consist of three principle essences- salt, sulfur and mercury.
- Book called “The Skeptical Chymist”in 1661
- said that element is a pure substance that is not made of other substances. Element therefore cannot be broken down into simpler substances.
- rejected a concept proposed by the alchemists notably Paracelsus that matter consist of three principle essences- salt, sulfur and mercury.
- Book called “The Skeptical Chymist”in 1661
- said that element is a pure substance that is not made of other substances. Element therefore cannot be broken down into simpler substances.
Robert Boyle
Robert Boyle’s ideas
Corpuscles are primitive, indivisible, and whole particles.
This idea opposed Aristotle’s belief that matter is infinitely divisible.
Elements are the simplest substances that make up mixtures.
They cannot be broken down into other substances through chemical reactions.
Around ____, a French man named _____ used closed vessels and precise weight measurements in many experiments to achieve the following:
1789
Antoine Lavoisier
Antoine Lavoisier achieved what?
- disproved the principle of phlogiston, where heated metals were thought to lose a substance of negative weight. Metals, which gain weight when heated in open air, actually react with oxygen air, causing it to form a calx (metal oxide).
- air is not an element because it could be separated into several components. Lavoisier called it oxygen.
- He showed that water is not an element, because it was made of two substances.
Chemical atomic theory proposed by?
John Dalton (1766-1844)
John Dalton (1766-1844)
Chemical Atomic Theory
Chemical Atomic Theory
- Gases, and all chemically inseparable elements, are made of atoms.
- The atoms of an element are identical in their masses.
- Atoms of different elements have different masses.
- Atoms combine in small, whole number ratios.
3 Fundamental Laws
- Antoine Lavoisier’s Law of Conservation of Mass
- Joseph Proust’s Law of Definite Proportions
- John Dalton’s Law of Multiple Proportions
Dalton’s Atomic Theory:
First:
-Elements: Made of identical atoms, unique properties.
-Compounds: Formed by combination of different atoms, new properties.
second:
-one could compute the weights of elements (and their atoms) by looking at comparable amounts of the compounds they formed.
third:
-Atomic weights: Calculated relative to a reference.
-Dalton’s reference: Hydrogen = 1 atomic weight.
-Unit: Initially called dalton, now AMU (atomic mass unit).
Scientists who made headway in the concept of the element thanks to Dalton’s theory
- Joseph Gay-Lussac
- Amedeo Avogadro
- Dmitri Mendeleev
Joseph Gay-Lussac
- oxygen gas was made of 2 atoms of oxygen, and is a molecule not an atom
- element wasn’t necessarily made up of one atom
- oxygen gas was made of 2 atoms of oxygen, and is a molecule not an atom
- element wasn’t necessarily made up of one atom
Joseph Gay-Lussac
Amedeo Avogadro
- (the man who conceptualized the mole)
- Equal volume and number of particles of 2 gasses (In simillar condition) would differ because of its molecular mass
- (the man who conceptualized the mole)
- Equal volume and number of particles of 2 gasses (In simillar condition) would differ because of its molecular mass
Amedeo Avogadro
Dmitri Mendeleev
- published a periodic table of elements according to its weight
-Find patterns to discover new elements
From Lavoisier’s 33 elements, the century ended with
82
Atom is made up of
nucleus and the electrons
parts of a nucleus
protons and neutrons
The negatively charge particle was discovered by Joseph John Thompson through the cathode ray tube experiment.
electron
who discovered electron
Joseph John Thomson
how did they discovered the electrons
cathode ray tube experiment
neutral subatomic particles
neutrons.
neutrons proposed by
James Chadwick
positive charge
protons
positive charge was discovered by
Eugene Goldstein
who proved the discovery of proton
Ernest Rutherford
_____ related electricity to atoms
Michael Faraday
According to Michael Faraday
Atoms that behave the same way in chemical reactions have the same amount of electrical charge associated with them.
Joseph John Thomson
electricity was in particles that were part of the atom
Experimenting with cathode rays
established the mass and charge properties of these particles (Electrons).
plum-pudding model
Ernest Rutherford,
- studied radioactivity
- radioactivity occurred due to changes on a subatomic level, or changes
- two kinds of radiation: α (alpha) and β (beta)
- model with a positive nucleus at the center and electrons revolving like planets at a distance around it.
- Protons
Niels Bohr
- proposed that the electrons existed only at fixed distances from the nucleus at set “energy levels,” or quanta.
-proposed that the electrons “jumped” between energy levels by absorbing or releasing discrete amounts of energy. - Electrons can jump from one orbit to another by emitting or absorbing energy.
Quanta was first conceptualized mathematically by
Max Planck
James Chadwick
He discovered neutrons, neutral particles with a mass similar to protons, by studying radiation from beryllium that could displace protons.
needed to have a neutral charge that would allow them to smash into the nucleus without being repelled by electrons or protons
John Dalton model
billiard ball model, that all matter is composed of very small things which he called atoms.
J.J. Thomson model
plum pudding model, electrons surrounded by a volume of positive charge, like negatively-charged “plums”
Ernest Rutherford model
has a tiny, massive core called the nucleus. The nucleus has a positive charge. Electrons are particles with a negative charge. Electrons orbit the nucleus.
Niels Bohr model
Bohr model, electrons travel in defined circular orbits around the nucleus. Electrons can jump from one orbit to another by emitting or absorbing energy.
Erwin Schrodinger model
Electron cloud model, we cannot know exactly where an electron is at any given time, but the electrons are more likely to be in specific areas.
