#1: The Nucleus Flashcards
What is the scientific definition of “theory”
A well tested set of ideas that explains many disparate* observations.
*Disparate: different in kind, unable to be compared
Who proved the existence of atoms?
Albert Einstein
In what year were atoms proved?
1905
Who was the first to observe atoms?
Robert Brown
When were atoms first observed?
1827
How was the existence of atoms proved?
A math equation that predicted the motion of an object, moved by atoms, almost perfectly.
What is Brownian motion?
The motion of an object by atoms or molecules bumping into it.
What are atoms
Tiny, discrete particles that have specific properties depending on the arrangement of three subatomic particles: Proton, Neutron, and the Electron.
What is a proton?
A heavy and positively charged subatomic particle.
What is a Neutron?
A subatomic particle similar in mass to the proton, though it is neutrally charged.
What is an Electron?
A subatomic particle with the same amount of charge as a Proton, though negatively charged. It is also has almost no mass.
Where are protons and neutrons located?
In the Nucleus, giving them the name nucleons.
Where are electrons located?
Around the nucleus.
What is the deciding factor for what element an atom is?
Its protons.
What is an Atomic Number?
The number of protons in an atom.
Why are atoms the defining trait of an element?
Because the number of atoms in a nucleus almost always stays the same.
Why are neutrons important in a nucleus?
They keep the protons from tearing apart the atom.
Does every atom of the same element have the same number of neutrons in its nucleus?
No, atoms can be stable with certain different amounts of neutrons.
*Example:
An atom of Silver can have either 60 neutrons or 62 neutrons.
What changes depending on the number of neutrons in an atom?
The atom’s Relative Atomic Mass.
What is Relative Atomic Mass?
The number of protons added to the number of neutrons averaged across every type of that element’s isotopes.
What is an Isotope?
Types of an atoms of the same element that have different masses but the same chemical properties.
What does the word “Isotope” mean?
Same place, referring to how isotopes are the same atom and therefore belong on the “same place” on the periodic table.
What two things are different amongst different isotopes?
The number of neutrons and the mass number.
What is the Mass Number of a nucleus?
The total number of Nucleons in a Nucleus.
What is a Nucleon?
A Proton or Neutron.
What is the difference between Relative Atomic Weight and Mass Number?
Relative Atomic Weight is the average of all the relative atomic masses of all the atoms of a single element while Mass Number is the number of Nucleons in a Nucleus.
What is Atomic Theory?
The idea that everything is made up of atoms
