vet-tech-chem-ch-4-compounds-and-bonds

• a negatively charged ion, such as Cl-
• gained 1 or more electrons

• a positively charged ion, such as Na+
• lost 1 or more electrons
• all are from metals including H+ and NH4+

• a combination of atoms in which noble gas arrangements are attained by sharing electrons
• shared valence electrons
• 2 non-metals:
• writing electron dots:
• - exist list - total # valence electrons from all atoms in the compound, plus/minus charge
• - wish list - total # electrons that all atoms in compound would like to have (nearest noble gas)
• - wish list - exist list = # of bonding electrons
• naming:
• - end in -ide
• - use Greek prefixes to show how many of each atom needed. Mono- may be left off 1st atom.

the separation of positive and negative charges in a polar bond indicated by an arrow that is drawn from the more positive atom to the more

• covalent molecules where one end of it is + and the other end of the molecule is - because:
• - there is at least one polar covalent bond in the molecule
• - the molecule is asymmetrical or uneven in its shape

attractive forces between oppositely charged ends of polar molecules

• weak dipole bonding that results from momentary polarization of non-polar molecules
• aka London forces, Van De Walls forces
• weak forces from temporary dipoles between non-dipoles (happens occassionally when an electron orbits one bonded atom more than the other bonded one)

a sharing of 2 pairs of electrons by 2 atoms

the relative ability of a element to attract electrons in a bond

• <0.4 => non-polar covalent bond
• 0.4 - 1.8 => polar covalent bond
• > 1.8 => ionic bond

the group of symbols and subscripts that represents the atoms of ions in a compound

the attraction between a partially positive H atom and a strongly electronegative atom of F, O or N.

• in order of decreasing strength:
• - hydrogen bonding
• - dipole-dipole attraction (for polar molecules)
• - dispersion forces

• an atom or group of atoms hanving an electrical charge because of a loss or gain of electrons
• charged atom or group of atoms because of a loss or gain of electrons

• a simple attraction between 2 opposite charged ions after their atoms have transferred or exchanged electrons
• metal with non-metal

the difference between the number of protons (positive) and the number of electrons (negative) written in the upper right corner of the symbol for

• a compund of positive and negative ions held together by ionic bonds
• writing binary ionic compounds:
• - the + metal ion is always placed 1st, the non-metal - ion is placed last; the compund ends in -ide
• compounds whose metals have variable charges:
• - roman numeral after metal indicates charge (+) of metal.

the smallest unit of 2 or more atoms held together by covalent bonds

a covalent bond in which the electrons are shared equally between the atoms

a molecule that has only non-polar bonds or in which the bond dipoles cancel

a set of 8 valence electrons

• elements in Groups 1A-7A (1, 2, 13-17) react with other elements by forming ionic or covalent bonds to produce a noble gas arrangement
• usually 8 electrons in the outer shell
• atoms react such that they gain, lose or share electrons so as to have a total of 8 electrons in their valence (noble gas configuration)

a covalent bond in which the electrons are shared unequally between atoms

a molecule containing bond dipoles that do not cancel

a measure of the unequal sharing of electrons indicated by the difference in electronegativity

• a group of covalently bonded non-metal atoms that has an overall electrical charge
• ions composed of many (> 2) atoms, but act as a single ion with a single overall charge
• many are oxyanions
• many end in -ate or -ite; exceptions - Hydroxide OH-, cyanide CN-, ammonium NH4+ (cation)
• Naming:
• - metal placed 1st
• - polyatomic ion is placed last and is recognized as such, eg parenthesize if > 1 ion (needs subscript)
• hint - if ther are 3 types of atoms in the molecultes, then 90% of the time there is a polyatomic ion

a sharing of 3 pairs of electrons by 2 atoms

a theory that predicts the shape of a molecule by placing the electron pairs on a central atom as far apart as possible to minimize the mutual repulsion of the electrons