Wednesday, December 28, 2011

Binary and Ternary Compounds; Monatomic and Polyatomic Ions; Compound Formation; Rules of Writing Formulas - Chemistry HW 9/30/10

1. a.
 A binary compound is a chemical compound that contains exactly two different elements performing the function of an element.
Binary compounds are materials/substances that exhibit only one type of strong chemical bond: metallic, ionic or covalent.

A ternary compound is a compound containing of more than two different elements.
Ex., Na3PO4 (sodium phosphate) ; CaCO3 (calcium carbonate) ; H2SO4 (sulfuric acid)

A monatomic ion is an ion consisting of one or more atoms of a single element which has either a positive or a negative charge unlike a polyatomic ion, which consists of more than one element in one ion which are either positively or negatively charged. The charge carried by a polyatomic ion is the overall charge of all the atoms in the ion.
A monoatomic ion is an ion formed from a single atom by the loss or gain of electrons. 

A polyatomic ion, also known as a molecular ion, is an ion composed of two or more atoms covalently bonded or of a metal complex that can be considered as acting as a single unit in the context of acid and base chemistry or in the formation of salts. It is a group of atoms that behaves as a unit and carries a net electrical charge. The prefix poly- means many in Greek, but even ions of two atoms are commonly referred to as polyatomic. In older literature, a polyatomic ion is also referred to as a radical, and less commonly, as a radical group.
A polyatomic ion can often be considered as the conjugate acid or conjugate base of a neutral molecule.

Compounds are formed when two or more elements combine. They are formed from simpler substances by chemical reaction. Some compounds can be formed directly from their constituent elements. Other compounds are formed by reaction of an element with another compound. Compounds are also made by reaction of other compounds. Complex molecules such as proteins are formed by a series of reactions involving elements and simple compounds. Formation of a compound involves a chemical reaction, whereas a mixture can be created simply by the physical act of stirring items together.dp
If the valence electrons of an atom are not full then it naturally either "takes in" or "gives up" its outer electrons so it can obtain a stable outer orbital. The compounds are formed from the shared pair of electrons and the attraction forces they create.
The atoms within a compound can be held together by a variety of interactions, ranging from covalent bonds to electrostatic forces in ionic bonds. A continuum of bond polarities exists between the purely covalent bond and ionic bonds.
The new substance has some properties that are like the original substance and some that are different.

Rules in writing formulas:
  • First, write the formula of the cation or the symbol for the positively charged ion (this will almost always be a metal)
  • Next, write the formula of the anion or the symbol for the negatively charged ion next (this is usually a nonmetal)
  • The compound, although consisting of charged particles, is neutral. The formula should indicate the smallest number of cation and anion units that should be combined to give an overall charge of zero.
  • Subscripts are used to show how many ions of each part are in the compound. They are used to balance the charge of the ions.
·         Write the correct charge above each ion
·         Reduce the formula to the simplest form by dividing the subscripts by any common multiple

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