Ancient Greek Philosopher, who was the first person to come up with the idea that Atoms are indivisible and differ in shape and size.
Who is Democritus?
100
Believed that elements were made up of tiny particles called atoms. These atoms can combine with other atoms to form compounds. He believed that atoms were indivisible. He lived in the 1800's
who is John Dalton?
100
Subatomic particle without an electric charge present in the nuclei of atoms.
What is a neutron
100
Subatomic particle present in the nuclei of atoms with a positive electric charge.
What is a proton
100
All elements are made of tiny indivisible particles called atoms.
All atoms of a given element are alike but the atoms of one element differ from the atoms of every other element.
Atoms are not created, destroyed or converted into other kinds of atoms during chemical reactions. They are simply rearranged into new compounds.
Compounds result from the chemical combination of a specific ratio of atoms of different elements.
What are Dalton's Postulates
200
He believed that everything was made up of four elements. Fire, Earth, Water and air. His view stood for thousands of years.
who is Aristotle
200
In the late 1890's he found that atoms of an element can emit tiny negative particles, which we now know are electrons.
who is J.J. Thompson?
200
A subatomic particle with a negative electric charge found in all atoms.
What is an electron
200
Conceptual model developed by Earnest Rutherford with a positively charged nucleus.
What is the nuclear atom
200
In any compound all samples of that compound will be made of the same elements
What is Law of constant composition
300
credited with thinking that atom might be like a plum pudding with Electrons distributed randomly about the atom.
Who is William Thompson (Lord Kelvin)
300
He designed the experiment to prove or disprove the plum pudding model.
Who is Ernest Rutherford?
300
A high vacuum apparatus that produces a luminous image.
What is a cathode ray tube
300
A positively charged particle with two protons and two neutrons
What are alpha particles
300
The mass of a system must stay the same if no mass is added or taken away.
What is Law of conservation of mass
400
won the Nobel Prize for physics in 1922 for his work on understanding the structure of atoms.
who is Niels Bohr?
400
Invention of soda water, but best known for his discovery of isolating and discovering oxygen.
who is Joseph Priestley?
400
Model that was abandoned after the discovery of atomic nuclei.
What is the plum pudding model
400
Measure of the tendency of an atom to attract a bonding pair of electrons.
What is electronegativity
400
When elements combine they do so in small ratios
What is Law of multiple proportions
500
Researched and promoted alternative crops to cotton, such as peanuts, soybeans, & sweet potatoes. Found many recipes and household uses for peanuts
who is George Washington Carver
500
researched threat to the Earth’s ozone layer of chlorofluorocarbon gases. Found the ozone hole over Antarctica.
who is Mario Molina?
500
The first chemistry book published by Antoine Lavoiser
What is Traitè Èlèmentaire de Chemie
500
Helium and a few other very light elements were formed within about three minutes of the "big bang", and that the next 23 elements are formed mostly by nuclear fusion.
What is the present belief
500
The Geiger-Marsden experiments that led to the discovery of a positive nulceus