A&P Chemistry Flashcards
Atomic number
Total number of protons in an atom
determines what type of atom it is
NO 2 elements with the same number of protons
Atomic number and electrons
Atoms usually contain the same number of protons and electrons
Mass number
Total number of protons and neutrons in an atom
Element
Substance composed only of atoms with same atomic number
Isotopes
Atoms with same number of protons but different numbers of neutrons
Different mass number
Atomic Mass
Actual mass of an atom of a specific isotope
Measured in atomic mass units (amu) or daltons
One amu = 1/12 mass of a carbon-12 atom
1 amu = Very close to the weight of one proton or one neutron
Atomic Weight
average mass of an element, including different isotopes in proportion
avgmass of all the isotopes of an atom
close to mass number of most common isotope
elements
118 total known elements, 94 natural, 24 can be physically or chemically derived
make up both living and non-living matter
Four elements account for 96% of elements in the body
Oxygen (65%)
Carbon (19%)
Hydrogen (10%)
Nitrogen (3%)
CHON
8 elements = 3.8%
Sulphur, sodium, chlorine, calcium, phosphorus, iron, magnesium, & potassium
SSCCPIMP
Trace elements (<0.2%) of others
aluminum, boron, fluorine, zinc, iodine, tin, selenium, chromium, cobalt, copper, manganese, molybdenum, vanadium
Atoms are electrically neutral
Every positive proton is balanced by a negative electron
unfilled valence shell
Atoms with unfilled valence shell are reactive and tend to react with other atoms to fill outer shell
full outer shells are inert
Do not readily react with other atoms; more stable
Atoms that have gained or lost electrons are no longer electrically neutral and become…
ions
positive ion
Called a positive ion or cation
negative ion
Called a negative ion or anion
difference between a molecule and a compound
Molecules = when 2 or more atoms share electrons and form chemical bonds
Compounds = a combination of 2 or more different elements
all compounds are molecules, Not all molecules are compounds
chemical bonds
Ionic bonds
covalent bonds
hydrogen bonds
chemical bonding
atoms want to fill there valence shells by either receiving, donating, or sharing electrons
This creates chemical bonding
Chemical bonding creates molecules
Ionic bonds
electrical attraction between cations and anions
Involve transfer of one or more electrons from one atom to another to achieve stability
Ionic bonds are…
These are relatively strong when NOT in solution, but VERY weak when placed in solution
When molecules with ionic bonds are placed in solvent (water) they tend to dissociate (break apart) into ions
electrolytes
When molecules with ionic bonds are placed in solution they tend to dissociate (break apart) into ions
These ions are then called electrolytes
Example: NaCl dissociates into the electrolytes Na+ & Cl-
When molecules with ionic bonds are placed in solution (water) they tend to dissociate (break apart) into ions, which are called…
electrolytes