Atomic Theory
This philosopher proposed that matter was formed of small pieces that could not be cut into smaller parts.
Who is Democritus?
He discovered neutrons.
Who is James Chadwick?
This is the number of protons in an atom, in the nucleus of an atom.
What is atomic number?
He made the first periodic table.
Who is Dmitri Mendeleev?
This man is an English chemist and thought that atoms were like smooth, hard balls that could not be broken into smaller pieces.
Who is John Dalton?
This is a negatively charged particle.
What is an electron?
Just below the atomic symbol is this, represented by a letter.
What is chemical symbol?
This is the average mass of all the isotopes in an element.
What is atomic mass?
This man discovered electrons in 1897.
Who is J.J. Thomson?
What is a nucleus?
This is represented in atomic mass units.
What is atomic mass?
The first periodic table was made in this year.
What is 1869?
This man discovered protons in 1911. And, ironically enough, was one of Thomson's students.
Who is Ernest Rutherford?
This is a positively charged particle.
What is a proton?
What is a period?
A.M.U stands for this.
What is atomic mass units?
In 1913 he suggested that electrons are found only in specific orbits around the nucleus, and was a student of Ernest Rutherford.
Who is Niels Bohr?
This has no electric charge and was hard to find.
What is a neutron?
The elements in a column form this, sometimes called a family.
What is a group?
The improved version of the periodic table was established in this year.
What is 1871?