1.2 The Nuclear Atom Flashcards
Subatomic particles
particles inside an atom (protons, neutrons, electrons)
Mass of proton
1
Mass of neutron
1
Mass of electron
1/2000 (0)
Charge of proton
+1
Charge of neutron
0 (neutral)
Charge of electron
-1
Nucleus
very dense core of an atom consisting of protons and neutrons
Nucleons
protons and neutrons
What holds an atom together?
electrostatic attraction between protons and electrons
A (subatomic particles)
mass number
Z (subatomic particles)
atomic number
Find neutrons (given A and Z)
A - Z
Properties of a neutral atom
same number of electrons and protons
Ion
atoms of the same element with a different number of electrons (lost/gained electrons)
Isotope
atoms of the same element with a different number of neutrons
Relative atomic mass formula
(mass1 * abundance1 + mass 2 * abundance2…) divided by 100
Mass spectra
device used to record percentage abundance of isotopes
Oxide ion (in the form A, Z, X, i+-)
16, 8, O, 2-
Why isn’t the relative atomic mass always a whole number in the periodic table?
it measures the average mass of it’s isotopes which might not necessarily be an integer
Natural abundance
relative percentage of an isotope compared to all other isotopes of that element on earth
Natural abundance of Cl-35 and Cl-37 (Ar = 35.5)
Cl-35: 75%; Cl-37: 25%
Why do isotopes share chemical properties?
change in the number of neutrons does not affect electron arrangement which determines chemical properties
Two main isotopes of U
U-235 & U-238
Why is one isotope of U preferred in nuclear reactors?
U-235 is preferred due to better fission capabilities of their lighter mass
Main mass of an atom is contained in?
the nucleus
