The Nucleus (1) Flashcards
What are isotopes?
Isotopes are atoms of the same element with different numbers of neutrons and atomic masses.
What determines what an atom is?
The atomic number determines the atom
Why are elements defined by their atomic number?
Their number of protons rarely change.
What is the organization of isotopes?
(element name)-(mass number)
example: gold-197
What do we call the number of protons in an atom?
Atomic Number
What is the + or - symbol on the top right of the element called?
The charge
What is the origin of the word “atom”?
Chemical term that comes from Greek words meaning “indivisible”.
What are the average masses of all the atoms of an element?
Relative atomic mass
What is the mass number?
number of protons + neutrons in an atom
Where is the atomic number in the element?
Top left of the element
Why do neutrons have little affect on an atom’s properties?
Neutrons have no charge
Where is the mass number in the element?
Bottom middle of an element.
What allows protons to be packed into the nucleus without repelling each other too much?
Neutrons “buffering” the protons’ repulsion of each other
What is a well-tested set of ideas that explains many disparate observations?
Theory
What do we call the random motion of particles in a fluid?
Brownian motion
What is the plural name for “nucleus”?
Nuclei
What is about 1800 times smaller than the other subatomic particles?
The electron’s size compared to protons and neutrons
Which part of an atom is most chemically active?
Electrons
What made Robert Brown’s pollen grains move randomly in water?
Atomic collisions
