Chem Capter 3

Chemical nomenclature

is the systematic way of naming chemical compounds

Chemical formulas

combined specific ratios elemental symbols and subscripts to represent compounds also known as as a formula unit. Compounds exist in different forms a covalent/molecular compound or ionic compound.

Chemical symbols

combined to give compounds. CO= carbon monoxide is made up of one carbon and one oxygen atom.

Subscripts

indicate how many of each element are present. CO2= one carbon and two oxygen.

If parentheses are present on a chemical compound

distribute the number outside the parentheses to the atoms inside the parentheses Ca(NO3)2 one calcium, two nitrogen, six oxygen

How many of each atom are in Al2(SO4)3

12 oxygen, two aluminum, three sulfur

Ionic compounds

3-D lattice atoms bonded in a repeating pattern. Metals and nonmetals or clusters of nonmetal atoms. Held together by ionic bonds. ex.) NaCl

Covalent/molecular compounds

exist as individual molecules. Are always nonmetals. Held together by covalent bonds. ex. CO

General naming rules

depends on the order of the elements. The first element's name is unchanged in the second element's name is altered with -ide, -ate, -ite.

Diatomic compound

two of the same atoms attached only seven and exist as gases. Naming: O2- oxygen gas or oxygen. Can refer to the element the same as it is written on the periodic table or put gas

Covalent/molecular compounds naming

nonmetals only the general rule is it always ends with -ide and uses Greek prefixes (memorize) ex. N2O3 dinitrogen trioxide. If there's only one of the first atom do not use mono. The second atom always uses a prefix. If the prefix ends in a/o an element starts with a vowel drop of the vowel. Exceptions- H2O=water and NH3= Ammonia

Ions

atoms that have a charge because they have gained or lost electrons.

Cations

lose electrons resulting in a positive charge in our formed from metals

Anions

gain electrons resulting in a negative charge formed from nonmetals.

Ion containing compounds

every ionic and acid compound contains ions. Split the compound the cation always comes first. Compounds must be neutral. (notes)

Monoatomic ions

one element with a charge. Determine the charge from the periodic table and the black line. Column gives a fixed charge shaded region. Our element is capable of multiple positive charges from 1 to 7. Exceptions- Zn 2+, Cd 2+, Ag+ have fixed charges

Cations

come from metals. First element name is unchanged and add ion. If capable of multiple charges, also use a Roman numeral to indicate the charge. ex. Na+ Sodium ion, Fe+ Iron (I) ion, Fe+2= Iron (II) ion

Anions

come from nonmetals second element name is altered w/-ide and add ion. Cl- = chloride ion & N³-=Nitride ion

Polyatomic ions

two or more elements with a charge. Positive ion -ium ending. Non-oxygen negative ion -ide ending. All halogens act the same. If all atomic ion has the most common/normal number of oxygen ends in -ate. One less oxygen -ite, two less oxygen ends in -ite & hypo- prefix, one more oxygen ends in -ate & per- prefix. Polyatomic ions with different number of oxygen still have the same charge, but if it has a different number of hydrogen, it will have a different charge

If a polyatomic ion gains hydrogen

if one hydrogen is added add hydrogen prefix if two hydrogen are added add dihydrogen prefix. ex.) HPO4 hydrogen phosphate ion, H2PO4 dihydrogen phosphate ion

Ionic compounds

always write the lowest ratio. The cat ion remains unchanged and use a Roman numeral if capable of multiple charges. The anion is altered, monoatomic -ide or polyatomic -ate or -ite.

Writing ionic formulas

must use charges and compounds must be electrically neutral. If the charges are equal, you can leave it alone.

Ionic hydrides

ionic compounds that contain water molecules within their solid structure. Number of water molecules are indicated with formula. Anhydrous- water is removed. Use ionic rules than indicate the number of waters by using a Greek prefix and hydrate. (the penta hydrate bs)

Acids

typically start with hydrogen. Monoprotic- one ionizable hydrogen (HCl), Polyprotic- or more ionizable Hs (H2SO4). Acids are technically covelant compounds but acts like ionic compound since they have charges.

Naming acids

name is derived from how many elements present by changing anion ending.

Binary acid

two elements- hydro____ic acid. HCl- hydrochloric acid H3P hydrophosphoric acid

Polyatomic acid

three or more elements keep anion prefixes if they exist. Anions ending in -ate become -ic acid. HClO3 chloric acid. Anions ending in -ite become -ous acid. HClO- Hydrochlorous acid