Chem. Quiz #1 - Covalent/Ionic Bonds

What is an Ionic Bond?

an attraction between two atoms of opposite charges, namely a metal and nonmetal

• electrons transferred from the metal to the nonmetal creating ions + therefore attraction

What is a Covalent Bond?

a bond formed by the sharing of a valence electron, namely between 2 non-metals or 1 non-metal and a metalloid

What are the properties of an Ionic Bond?

soluble, conductive in water, + have high melting points

What are the properties of a Covalent Bond?

not soluble, non-conductive, + have low-melting points

What is a Chemical Bond?

the attraction between an atom’s nucleus + another atom’s valence electrons

• covalent, Ionic, or metallic

What is the exception to the normal Ionic Bond?

Beryllium - metal that covalently bonds with other metals

What is Lattice Energy?

energy released in the formation of an Ionic bond

What are the physical properties of ionic compounds?

hard, brittle, solid at room temp.,

• poor conductors when solid but good conductors when melted/dissolved (ions separated)

How do you draw a Lewis Dot structure?

draw the element’s symbol + its valence electrons on its 4 sides

What is a molecule?

an uncharged group of 2+ atoms held together by covalent bonds

What is true about the bonds in compounds made up of several molecules?

the bonds between the atoms (covalent) are strong but those between the molecules are weak 

What are the physical properties of a Covalent Compound?

not soluble, non-conductive, + have low melting points

• liquid/gas at room temp.

What is a Diatomic Molecule? What are they?

two of the same element bonded covalently

H, O, Br, F, I, N, Cl

How can we determine the kind of bond two elements have?

compare (subtract) electronegativities

• if the difference is <0.3, then it is non-polar covalent (electrons shared equally)

• if the difference is 0.3-1.7, then it is polar covalent (electrons shared unequally)

• if the difference >1.7, then it is Ionic 

Name the prefixes 1-10

mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca

How do we name Covalent Compounds?

1. use prefix + name of 1st non-metal

2. use prefix + name + -ide of 2nd non-metal

Ex. P₂O₅ —> Diphosphorus Pentoxide

What is the Formula Unit?

the lowest ratio of Cations: Anions

Ex. P10O6 would reduce to P5 O3

How do we name Ionic Compounds?

1. name first element (metal)

2. name second element w/ -ide

Ex. Na₂Br —> Sodium Bromide

What is true about the charge of an Ionic Compound?

it must be 0, meaning all the positives must cancel out the negatives

Ex. Use the table to figure out the formula for Magnesium Phosphide.

Mg₃P₂

Magnesium: +2

Phosphorus: +3

There must be 3 Mg ions to cancel out 2 Phosphorus ions

How do we write the names of Transition Metals from a formula?

1. Name the cation

2. write its charge in parenthesis

3. name the anion w/ -ide ending

Ex. Fe₂O₃ —> Iron (III) Oxide.

Explain

O₃ —> -6

This means that Fe₂ must = +6

6 / 2 = 3, meaning that one Fe = +3

Therefore, the charge of the cation is +3 and belongs in parenthesis

What is a Polyatomic Ion?

a group of atoms bonded covalently that still has a charge

How do we name Polyatomic Bonds?

1. name metal/ Polyatomic ion

2. write its charge in parenthesis

3. anion w/ -ide ending

Name all of the Electron Geometry Shapes. What are their angles + Bonding Pairs?

Linear: 180*, 1-2 BP

Trigonal Planar: 120*, 3 BP

Bent: <120*, 2 BP, 1 LP

Tetrahedral: 109.5*, 4 BP

Trigonal Pyramidal: <109.5*, 3 BP, 1 LP

Bent: <109.5*, 2 BP, 2 LP

Trigonal Bipyramidal: 90* + 120*, 5 BP

Octahedral: 90*, 6 BP

What is an Intermolecular Force and what are the main 3?

IMFs are the forces of attraction that form between molecules 1. Hydrogen Bonds

2. Dipole-Dipole Forces 3. London Dispersion Forces

Explain the 3 IMFs.

1. Hydrogen Bonds: between hydrogen + F,O, or N (highly electronegative)

2. Dipole-Dipole: a strong bond between polar molecules

3. London Dispersion Forces: a weak bond between two non-polar molecules