Anatomy Of The Atom Flashcards
Matter
Substance that occupies space and has mass
Elements
Form of matter w/ chemical & physical properties that can’t be broken by ordinary chemical reactions
Elementos (quantity)
118 elements, but only 92 occur naturally. The rest are synthesized in labs and are unstable
Four common elements to all living organisms
Oxygen, Carbon, Hydrogen, Nitrogen (in order)
Compound
Substance consisting of 2 or more elements
Atom
Smallest unit of matter that retain chemical properties of an element
Two regions of an atom
Nucleus and outermost region (or electron cloud)
Nucleus of an atom
Contains protons and neutrons
Outermost region (electron cloud) of an atom
Contain electrons in orbit around the nucleus
Hydrogen exception (subatomic particles)
One proton and one electron w/ no neutrons
Protons (weigh)
+1 charge, 1 (amu or Dalton), 1.67 x 10^-24 grams.
Neutros (weigh)
0 charge, 1 (amu or Dalton), 1.67 x 10^-24 grams.
Electrons (weigh)
-1 charge, 0 (amu or Dalton), 9.11 x 10^-28 grams.
Uncharged, neutral atoms
Electrons and protons have a equal number leaving the atom w/ no net charge.
How much is empty space in an atom?
More than 99%. The reason atoms don’t go through each other is because electrons repel each other (negative charge)
Atomic number (Z)
Number of protons
Isotopes
Same # of protons, but different # of neutrons (different forms of the same atom)
Mass number (A)
of protons and neutrons
Atomic mass
Is the mass # of its naturally occurring isotopes.
Stable atomic configuration
Lower level of potential energy
Radioactive isotopes or radioisotopes
Isotopes that emit high energy particles due to unstable nucleus.
Radioactive decay
Energy loss when an unstable atom’s nucleus releases radiation.
Radioactive isotopes or radioisotopes (properties)
Same reactive and chemical behavior, each element has a decay rate, and emissions are detected even at low levels.
Decay rate
Rate of particle emission
Types of radioactive decay
Alpha particles, Beta particles, and Gamma particles.
Alpha decay
He(element) Z -2 & A -4
Penetration: skin deep
Shielding: clothes/paper
Beta decay
Z +1 & A no effect
High energy electron
Penetration: sub cutaneous (below skin)
Shielding: aluminum
Gamma decay
High energy photon and no effect on nucleus.
Penetration: any internal tissue.
Shielding: lead plates
Radiation in cancer treatment
Cause mutation in DNA of cancer cell killing it.
Radioactive dating
Determine the age of something usually using carbon 14 (C-14)
N=No e^-0.693T/ T½
N = amount of radioactivity after time (t) No = amount of starting radioactivity -0.693 = ln(2) T = amount of time sample is left to decay T½= half life e = natural logarithm
