Development of Atomic Models
The Modern Atomic Model
Patterns in the Elements
Organization of Periodic Table
How Elements Form in Stars
100
The Greek philosopher, Democritus proposed that idea that matter is formed into small pieces that could not be cut into smaller parts. He used this Greek word which means "uncuttable".
What is atomos?
100
This model of the atom describes a nucleus that contains protons and neutrons and is surrounded by a cloudlike region of moving electrons.
What is the modern atomic model?
100
In 1869, this Russian scientist discovered a set of patterns that applied to all the elements.
Who is Dmitri Mendeleev?
100
The Modern Periodic Table has the elements arranged in order by increasing _________ ____________.
What is atomic number
100
By studying the sun and other stars, scientists have formed hypotheses about the origins of _____________ on Earth.
What is matter?
200
All elements are composed of atoms that cannot be divided. All atoms of the same element are exactly alike and have the same mass. Atoms of different elements are different and have different masses. An atom of one element can not be changed into an atom of a different element. Atoms cannot be created or destoyed in any chemical change, only rearranged. Every compound is composed of atoms of different elements combined in a specific ratio.
What is Dalton's Atomic Theory or a Summary of Dalton's Ideas?
200
This particle of the atom is electrically neutral and was discovered by British scientist, James Chadwick.
What is the neutron?
200
This is the average mass of all the isotopes of an element.
What is the atomic mass?
200
The modern periodic table is organized in horizontal rows called___________.
What are periods?
200
A state of matter that consists of a gas-like mixture of free electrons and nuclei of atoms that have been stripped of electrons.
What is plasma?
300
In 1897 this British scientist found that atoms contain negatively charged particles (later named electrons)
Who is J. J. Thomson?
300
The unique number of protons in the nucleus of an atom.
What is the atomic number?
300
In 1869, Mendeleev published the first __________ _______________.
What is the periodic table.
300
The elements contain repeating patterns and are arranged in columns called __________. These columns contain elements with similar characteristics.
What are groups or families?
300
This is a process by which two atomic nuclei combine forming a larger nucleus and releases huge amounts of energy.
What is nuclear fusion?
400
This scientist inferred that an atom's positive charge must be clustered in the nucleus.
Who is Ernest Rutherford?
400
The unique number of protons in the nucleus of an atom.
What is an element's atomic number?
400
The modern periodic table is arranged by increasing ____________ as opposed to the atomic mass.
What is the atomic number?
400
The elements are listed in the Periodic Table by chemical __________ which contains either one or two letters.
What are symbols?
400
Astronomers generally agree that the matter in the sun and its plants came from a ___________, which was an explosion that broke apart a massive star billions of years age.
What is a supernova?
500
In an atom the numer of ___________ equals the number of protons.
What are electrons?
500
Atoms with the same number of protons and a different number of neutrons.
What are isotopes?
500
Mendeleev's Periodic Table arranges the elements according to this increasing ____________ _________.
What is atomic mass?
500
This is determined from the combined atomic mass percentages of all of the isotopes of an element.
What is the average atomic mass?
500
This occurs in stars on a huge scale, combines smaller nuclei into larger nuclei creating heavier elements.
What is nuclear fusion?
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