Ionic Charges and Naming

Unit 2 Notes

Ionic Charges of the Elements

• Elements in the same group of the periodic table have similar properties.– Example: forming ions with same charge.

• Alkali metals lose 1 electron, Alkaline Earth metals lose 2 electrons (Al loses 3).

• Halogens gain 1 electron. O, S, and Se each gain 2 electrons. N and P gain 3 electrons.

Metal Ions

• Refer to table 5.3 (pg. 120) for ions formed by metals.

• Metals with more than one common ion use roman numerals when naming.– Example: Cu+ and Cu2+ ions are called Copper(I)

and Copper(II) ions. The Roman numeral represents the charge of the ion. (remember, subscripts represent how many, not necessarily the charge)

In-Class Assignment

• Pg. 121, example 3 and example 4

Polyatomic Ions

• Tightly bound groups of atoms that behave as a unit and carry a charge. (Table 5.4)

• Most end in –ite or –ate.– Exceptions = ammonium NH4

+ , cyanide CN- , and hydroxide OH-

• Generally –ite means one less atom compared to the –ate. – Example: HSO3

- (Hydrogen sulfite) and HSO4-

(Hydrogen sulfate)

Combining Ions

• When two ions combine the sums of the charges of each ion determines the overall charge of the polyatomic ion.– Example: H+ + CO3

2- • The polyatomic ion is written as HCO3

- because the one extra proton the Hydrogen ion combined with the two extra electrons of the carbonate ion results in an overall negative charge (1 more electron than protons).

Systemic Names

• Binary Ionic Compounds– Composed of two elements– Electrically neutral

• Example 5 (together on pg. 126)– Concept practice (do on your own)– Practice problem (do on your own)

Naming Binary Ionic Compounds

• Remember “bi” means 2• This means the binary ionic compounds only

involved 2 different ions. (not 2 polyatomic ions)– Example 6– Concept practice– Practice problem

Ternary Ionic Compounds

• Ternary compounds contain atoms of three different elements.– Example 7 (pg. 129)– Concept practice– Practice problem

Binary Molecular Compounds

• Ionic charges are not used• Use prefixes – The names of all binary compounds (both ionic

and molecular) end in ide.• It is important to know if the elements are

nonmetals or metals– Example 9 (pg. 131)– Practice problems 25 & 26 (pg. 132)

Naming Acids