chapter 4 Flashcards
What makes a stable nuclei
the force of attraction and repulsion are balanced
which elements usually have a stable nuclei, and which don’t
element below atomic number #19 usually have a stable nuclei, elements atomic number #20 and above usually don’t have stable nuclei
what makes a nuclei unstable?
too many or too few protons compared to number of neutrons therefore the forces are unbalanced
Radiation
energy emitted by unstable nuclei to become more stable
radioisotopes
isotopes that emits radiation
Transmutation
change in number of protons in nucleus (atom of an element converted to a different element)
Which elements are produced artificially?
elements #93 or higher on the periodic table are produced in nuclear labs
How does emitting radiation help atoms be more stable?
an unstable nucleus forms a more stable, lower energy nucleus
What are the types of radiation?
alpha particles, beta particles, positron, Gamma rays
Alpha particles
identical to helium nucleus (2 protons, 2 neutrons, mass number 4, atomic number 2, charge of 2+
beta particles
high energy electron with a charge of 1-, mass number 0
when do beta particles form?
when a neutron in an unstable nucleus changes to a proton and an electron.
positron
positive 1+ charge with a mass of 0, it is an antimatter
when is a positron produced?
it is produced by the unstable nucleus when a proton is transformed into a neutron and a positron
How are gamma rays produced?
when a positron and an electron collides
ionization radiation
when radiation hits molecules in its way, electrons may be knocked away forming unstable ions
why is ionization energy harmful for humans
if it passes through human body, it might interact with water molecules removing electrons and producing H20+
Which type of cells are most sensitive to ionization radiation? and examples?
cells that undergo rapid cell division, such as bone marrow, skin, reproductive organs, cells of growing children and cancer cells
shielding
materials used to provide protection from radioactive sources
Alpha particles protection?
paper, skin, clothing
how do alpha particles travel?
in the air for a few cm before they collide with air molecules , acquire electrons and become helium
Beta particle shielding
heavy clothes such as lab coats and gloves
which radiation particle has the largest mass?
alpha particles
Gamma rays protection
only dense shielding such as concrete and lead.