Atomic Structure Flashcards
Which Scientist’s model of the atom changed when subatomic particles were discovered?
John Dalton
Name the three subatomic particles
Protons, electron, neutron
What is the mass of a proton?
1
What is the mass of a neutron?
1
What is the mass of an electron?
Almost zero / very small
Which subatomic particles are found in the nucleus?
Protons and neutrons
Where is most of the mass of an atom concentrated?
In the nucleus
What is the mass number of an atom?
The total number of protons and neutrons in the nucleus
What is the atomic number of an atom?
The number of protons. This is unique to each element.
Which subatomic particles are always found in equal numbers in atoms?
Protons and electrons (there must be the same number of positively charged protons and negatively charged electrons)
Sodium has a mass number of 23 and an atomic number of 11. How many protons, electrons and neutrons does it have?
Protons 11
Electrons 11
Neutrons 12
What are isotopes?
Atoms of the same element containing the same number of protons but different numbers of
neutrons.
What is the difference between carbon-12 and carbon-14?
Carbon-12 has 6 neutrons and carbon-14 has 8 neutrons (they both have 6 protons and 6 electrons)
Why do some elements have a mass number that isn’t a whole number?
The element has different isotopes. The mass number is an average of the isotope masses, taking into account the abundances (amounts) of the isotopes.
What is the charge on a proton?
Positive / +
