Review for Bonding and Compounds Test

Compound formulas Ions must add up to zero charge What metal ion is present in Na 2 O? Binary compounds (two elements) must end in – ide. What is the ending for Fe 2 O 3 ? When naming a compound, transition metals must have a Roman numeral to indicate charge of the metal ion What is the Roman numeral in the name of the above compound?

Answers -ide +3

Electrons in Bonds What’s the goal? How is the goal achieved for ionic compounds? How is the goal achieved for covalent compounds? What is a polyatomic ion? Is OH -1 a polyatomic ion?

Answers 8 electrons in outer shell Transfer from metal to non-metal to achieve octet Share of valence electrons to achieve octet More than one atom with a charge Yes

Electron Transfer What charge does calcium have after losing its outer electrons? How many electrons are transferred when calcium combines with sulfur? How many electrons are transferred when sodium combines with sulfur? How many electrons are transferred when aluminum combines with sulfur?

Answers

Characteristics of Ionic Compounds Describe potassium sulfide. Describe lithium phosphate. Describe sodium hydroxide.

Answers For all three— Crystalline solid (many many atoms) High melting point Strong bonds

Characteristics of Molecular Compounds Describe carbon dioxide Describe ammonia (NH 3 ) Describe water at room temperature

Answers For all three – Liquid or gas Low melting point Strong bonds Few atoms together as individual molecules

Sketch a Molecular Compound Consider the formula Have only a few atoms (whatever is in the formula)

Sketch an ionic compound Many atoms Formula gives you the RATIO, not the total number of atoms

Mixtures Name a mixture How is it different from a compound? How is that different from an element?

Answers Salt Water Compounds are chemically bonded Elements are single substances

Valence What does valence mean? How do you determine valence electrons? What is the valence for potassium? What is the valence for oxygen? What is the valence for helium? What is the valence for fluorine?

Answers Outer Electrons Group A – Roman numeral on table gives valence (careful, that’s helium – can only hold 2) 7

Naming Compounds Which comes first in the name of a compound, metal or non-metal? What is the name of Li 2 O? What is the name of FeO? What is the name of Al 2 S 3 ?

Answers Metal Lithium oxide Iron (II) oxide Aluminum sulfide

Dot Diagramming What are the steps for drawing a dot diagram? Draw the dot diagram for the following: I 2 CH 4 CO 2 H 2 O NH 3

Answers Count up valence electrons Place atoms with least electronegative atom in center (usually the first in the formula) Give all atoms 8 electrons, sharing electrons – except hydrogen which can only have 2