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What are the three elementary particles?
Electrons (e-) negative
Protons (p+) positive
Neutrons (n) neutral
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_________ are the tiniest elementary particles.
Electrons
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Electrons
They carry a charge, and are not trapped in a nucleus; they are responsible for the chemical prperties of the atom.
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Protons
Carry a positive charge, equal and opposite to that of the electron. They are sequestered in the nubleus and cannot participate in chemical reactions.
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Neutrons
They have no charge, but like protons, have mass.
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________ ___________ is the basis for nuclear weapons, nuclear reactors, and nuclear medicine.
Nuclear Fission
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Prostate beams are used to treat
prostate, brian and lung cancers.
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PET
positron-emission tomography
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Which particle is often represented as a "planet" orgiting the "sun" (atomic mucleus)
Electrons
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Which particles form the nucleus?
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Mass of neutron
1,009 Daltons( atomic mass unit)
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Mass of proton
1,007 Daltons (atomic mass unit)
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A neutral atom of a particular element has an equal number of ________ and ________
electrons and protons (so the +and -charge cancel out)
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The number of _________ can vary.
Neutrons. The variation changes the atom's mass but not its chemical properties. Atoms which vary in the number of neutrons are called isotopes.
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Atomic number is what
number of protons
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Mass number is what
Sum of protons and neutrons
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Graphic objective 8. Describe the charge, mass, and relative location of electrons, protons, and neutrons.
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Isotopes
number of neutrons that vary
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2H- Deuterium
an isotope of hydrogen; Deuterium plus oxygen makes up so -called havy water (D2O), a compound used as a tracer in metabolic studies.
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3H - Tritium
an isotope of hydrogen. tritium is unstable and a tritium atom will fall apart, on average, after 12 yrs. We call this half -life.
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Radioisotopes
Some combinations of protons and neutrons that are unstable.
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Covalent bonds
bond formed between two or more atoms that share electrons
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because atoms "want" to gain or shed electrons to fill outer shells, valence also describes hou many
positions one moves on the periodic table to rach a noble gas column
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Double covalent bond
when two electrons are shared equally
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Triple covalent bond is when
three electons are shared from each atom
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Polar covalent bond
This kind of bond means that the atoms have a patial charge on them, so it has poles and its called polar. Because this kind of bond has characteristics of a polor bond and a covalent bond... polor covalent bond
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Ionic bond
when atoms hang out together because they have opposite charges.
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What atoms are in the human body that form polar covalent bonds
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Ionic bonds are formed between
metal and non-metal ions
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In a polar covalent bond that pull on eledtrons is measured in a quality called
electronegativity
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Hydrogen bonds
are specialcharacteristics of compounds hat contain haydrogen and oxygen, hydrogen and ditrogen, and hydrogen and sulfer
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Dipole
More positve charges at one end, more negative charges at the other
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Acid
a substance that dissolves in water to form one or more H+ ions and one or more anions
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Base
is a substance that dissolves in water to form one or more OH- ions and one or more cations
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acids on the human body include
- gastric juice
- vaginal fluid
- urine (most of the time)
- saliva
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bases in the human body include
- urin (only rarely)
- blood
- semen
- cerebrospinal fluid
- pancreatic juice
- bile
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the most important buffer system in human biology is the
carbonic acid-bicarbonate buffer system
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Buffer
acts as a H+ and /or OH- "sponge" so that pH is kept relatively contant
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pH
negative logarithm of the hydrogen ion concentration
log [H+]
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