Chapter 5: Ions & Ionic Compounds

1. Chapter 5: Ions & Ionic Compounds Jessica Alphonse

2. Chemical Reactivity • Some elements are very reactive and some are not. • The way you can tell how reactive an element can be, all depends on electronic configuration. • Ex. O2= 1s2,2s2, 2p4. • The 2p orbital in o2 have four electrons. • The noble gases are the least reactive because they already have 8 electrons and follow the octet rule. • “Alkali metals & Halogens are the most reactive because they have only one electron.” (Ch.5, p.158) • (Citation-Ch.5, p 158)

3. Valence Electrons & Stable Ions • The small number on the electron configurations represent how many electrons an atom has. • To find out how many electrons an atom has, simply look at the periodic table. • In order to form stable ions, atoms must gain or lose electrons to form stable ions. • Ion- “an atom that’s gained or lose one electron that has a negative or positive charge.”(Ch.5, p.161) • Cation- “an ion with a positive charge.” (Ch.5, p.161) • Anion- “an ion with a negative charge.”(Ch.5, p.161)

4. Ionic Bonding and Compounds • During an ionic bond, cations and anions should attract each other. • It takes a good amount of energy for electrons to be transferred from an atom from a negative to a positive charge. • Ionic compounds are very strong and have distinctive properties. • The compounds have ions that can’t be in fixed locations. They also are never gaseous when they reach a boiling temperature.

5. How to Name & Write Ionic Compounds/Formulas • To name an ionic compound, simply name the cation and the anion by borrowing any of the element name. • Ex. K+ = Potassium ion. • They’re also called binary ionic compounds because it contains two elements. • To write an ionic formula, it has to be balance. Therefore the positive and the negative charge must be the same. • Ex. Na+ & Cl- have 1 electron.

6. Polyatomic Ions • Polyatomic ions are a group of bonded atoms charged. • Polyatomic ions are also made out of several elements that are either positive or negative. • To name a polyatomic ion, most of them have oxygen; so the ending either has –ite or –ate. • Ex. Sulfide (SO2/3)= sulfate or sulfite. • When an ion has hydrogen, the prefixes have mono- or di-. • Ex. CO2 = carbon dioxide.

7. Citations • Meyers, R. Thomas, et al. • Holt Chemistry . Austin, TX: Rienhart & Winston, 2004 • Slide 2: Ch.5, p.158 • Slide 3: Ch.5, p.160-163 • Slide 4: Ch.5, p.166 & p.171 • Slide 5: Ch.5, p.176-178 • Slide 6: Ch.5, p.178