The Electrical Properties of Matter Charged Subatomic Particles

The Electrical Properties of Matter

Charged Subatomic Particles Protons – Positive Charge l Electrons – Negative Charge l Neutrons – No Charge l

Atoms l Atoms always have a net zero charge. l The number of protons is equal to the number of electrons.

Ions l Ions occur when an atom gains or loses an electron and gets a charge. l. A anion is an ion with a negative charge l More l. A cation is an ion with a positive charge l More l electrons than protons than electrons A group of bonded atoms that has a charge is called a polyatomic ion.

Ion Interactions l Unlike charges attract each other l Positive and negative charges will stick together. l Like charges repel each other. l Two negative charges repel each other. l Two positive charges repel each other.

Ionic Compounds Ionic compounds are formed when positive and negative ions are attracted to each other. l Ionic compounds have a net charge of 0. l

Formation of Ionic Compounds l Ions form compounds with no charge. l Example: H+ and S-2 l S-2 has a negative two charge. l Needs 2 H+ to have no charge. l Formula = H 2 S l Example: l The Al+3 and O-2 only way to even out the charges is 2 Al+3 and 3 O-2. l Formula: Al 2 O 3

Advanced Ionic Naming The positive charged ion comes first and keeps the name of the element. l The negatively charged ion comes second. The ending of the name is changed to –ide l l Na 3 As = Sodium arsenide l Al. N = Aluminum nitride

Advanced Chemical Formulas Periodic Table Labels l A periodic table can be used to determine the charge on an ion. l

Stock System of Naming l Some metals have more than one charge. l Examples: l Mercury can have a charge of +1 or +4 l Iron can have a charge of +2 or +3 l In ionic naming, these metals have a Roman numeral after their name to tell the positive charge.

Roman Numerals l l l One = I Two = II Three = III Four = IV Five = V l l l Six = VI Seven = VII Eight = VIII Nine = IV Ten = X

Advanced Formula Practice l Manganese (II) iodide l The charge is +2 on the manganese (Mn+2) l Iodide = iodine with a -1 charge. (I-1) l Mn+2 I-1 (Cross charges to get the subscripts) l Mn. I 2

Advanced Formula Practice l Mercury (IV) silicide l Mercury has a charge of +4 (Hg+4) l Silicide = silicon with a charge of -4 (Si-4) l Hg+4 Si-4 (Since the charges are the same number, you can just write the symbols together) l Hg. Si