ch 3 ionic bonds

ionic compounds are

formed from metals transferring electrons to nonmetals

charge when losing an electron

POSITIVE

charge when gaining an electron

NEGATIVE

cation

LOSE electrons to become POSITIVELY charged

anion

GAIN electrons to become NEGATIVELY charged

octet rule

in ionic and compound bonds, atoms gain or lose or share electrons to get 8 valence electrons (noble gas configuration)

metals …. electrons

LOSE

nonmetals …. electrons

GAIN (to complete outer shell)

anions are named by adding

IDE

when writing the symbol for ions, the subscript rarely goes above/blow…

-3 and 3

(so if -4 to 8, write +3)

ions in the body: Na+

principal cationo outside of the cell

regulates and controls body fluids

ions in the body: K+

principal cation inside of the cell

regulates body fluids and cellular functions

ions in the body: Ca²⁺

cation outside of the cell, 90% of calciu, in the body in bone occurs as Ca3 or CaCo3

major cation of bone, needed for muscle contraction

ions in the body: Mg²⁺

cation outside the cells; 70% of magnesium in body is in the bones

essential for certain enzymes, muscles, nerve control

ions in the body: Cl-

principal anion outside the cell

major anion of gastric juice, regulates body fluids

bonds in ionic compounds are

very strong

solids/crystals with high melting points

how do ionic bonds form

metals transfer e- to nonmetals, the ions are held together by attractions btwn opposite charges

how are formulas for ionic compounds written?

Metal Nonmetal

subscripts

ionic formula charges

sum of ionic charges must be zero

no overall charge, must cancel each other out

how to write ionic formula

write the ion symbols for each element - metal first always

ex: barium chloride

Ba²⁺ Cl^- → BaCl₂ (subscripts and cancelling out to get neutral charge)

polyatomic ion: NO^₃-

nitrate ion

polyatomic ion: SO^₄2-

sulfate ion

polyatomic ion: CO^₃2-

carbonate ion

polyatomic ion: NH^₄+

ammonium ion

polyatomic ion: PO^₄3-

phosphate ion

polyatomic ion: HCO^₃-

bicarbonate ion

polyatomic ion: OH^-

hydroxide ion

formula mass (molar mass)

adding the masses of each atom in the formula of the compound