ATOM ANTICS
Who is Democritus?
Dalton pictured atoms as solid spheres, somewhat like these round objects.
What are balls/spheres?
This particle has a negative electrical charge.
What is an electron?
This chart organizes the chemical elements.
What is the periodic table?
The atomic number tells you the number of these particles.
What are protons?
The Greek word atomos, from which we get "atom," means this.
What is indivisible or uncuttable?
J. J. Thomson's model compared an atom to this English dessert, with negative particles scattered through positive matter.
What is plum pudding?
These two particles are found in the nucleus.
What are protons and neutrons?
An atom is the smallest particle of one of these that retains all of its properties.
What is an element?
Add an atom's protons and neutrons together to get this number.
What is the mass number?
This philosopher rejected Democritus's idea and taught that matter was made of earth, water, air and fire.
Who is Aristotle?
Thomson's experiments provided evidence for this negatively charged subatomic particle.
What is the electron?
This nuclear particle has approximately the same mass as a proton but no electrical charge.
What is a neutron?
The identity of an element is determined by the number of these particles in its nucleus.
What are protons?
Atoms of the same element that contain different numbers of neutrons are called these.
What are isotopes?
In 1808, this English chemist revived atomic theory using experimental evidence rather than philosophical argument alone.
Who is John Dalton?
Rutherford fired these positively charged particles at a thin sheet of gold foil.
What are alpha particles?
Rutherford named this positively charged particle in 1919; James Chadwick discovered its neutral nuclear partner in 1932.
What are the proton and neutron?
An element has atomic number 12. Every atom of that element must contain exactly this many protons.
What is 12?
Carbon-14 has atomic number 6. This isotope therefore contains 6 protons and this many neutrons.
What are 8 neutrons?
Dalton's theory helped explain these two laws: one says matter cannot be created or destroyed, and the other says a pure compound always contains its elements in the same proportions.
What are the laws of conservation of mass and constant composition?
Rutherford expected nearly all his particles to pass straight through the gold foil. Some bounced sharply backward. This led him to conclude that an atom contains this.
What is a tiny, dense, positively charged nucleus?
An atom contains 17 protons, 18 electrons, and 18 neutrons. Its overall charge is this.
What is −1?
Two atoms both have 8 protons, but one has 8 neutrons and the other has 10. They are still the same element because they share this defining feature.
What is the same atomic number/number of protons?
An isotope has a mass number of 37 and contains 20 neutrons. Give its atomic number, number of protons, and—if the atom is neutral—number of electrons.
What are atomic number 17, 17 protons, and 17 electrons?