2.1 the nuclear atom Flashcards
what is an atom made up of?
protons, neutrons and electrons
Define atomic number.
the number of protons in the nucleus of an atom
How do you know how many electrons there are in an atom?
the same as the number of protons
Define Mass number.
the number of protons plus neutrons in the nucleus of an atom
How do you know how many neutrons there are in an atom?
mass number- atomic number
Define Ion.
charged particles that are formed when an atom loses or gains electrons
What is the charge of ions that gain electrons?
negative ion
What is the charge of ions that lose electrons?
positive ions
Define Isotope.
different atoms of the same element with different mass numbers (different numbers of neutrons in the nucleus)
What are the properties of isotopes?
they have the same chemical properties but have different physical properties (i.e. melting and boiling points)
What do chemical reactions depend upon?- as a reason why isotopes react the same way.
Isotopes have the same numbers of electrons, chemical reactions depend only on the number and arrangement of electrons not the composition
What do physical reactions depend upon?- as a reason why isotopes react different ways.
The different masses mean that their atoms move at different speeds.
Define relative atomic mass.
the average of the masses of the isotopes in a naturally occurring sample of the element relative to the mass of 1/12 of an atom of carbon-12
How do you calculate relative atomic mass?
(relative atomic mass- mass number of the lighter isotope / difference in mass number of two isotopes ) x 100
What can be measured by a mass spectrometer?
the proportion of each isotope present in a sample of an element
