Chemistry Exam 2

Bond between two non metals

Covalent Bonds

Bond between a metal and a nonmetal

Ionic Bonds

Non metals form binary molecules when they ______ electrons

Share

Metals form bonds by ______ electrons

Giving

This happens when the electronegativities of the atoms don’t balance each other out, causing an uneven pull of electrons (a net pull).

Polar bonds

_______ is formed when a metal becomes a positive cation and a nonmetal becomes a negative anion, and their opposite charges attract

Ionic compound

______ happen when two nonmetals share electrons to stick together, and they don’t have any charge

Covalent compounds

A group of atoms covalently bonded together that carries a net positive or negative charge

Polyatomic ion

An ionic compound that has water molecules attached to its crystal structure, which can be removed by heating.

Hydrated salt

Usually covalent molecules that can release H⁺ ions in water, and sometimes they have one H or more H atoms at the front

Acids

are covalent inside, but they act ionic when dissolved in water.

Binary acids

hydrogen + oxygen + a nonmetal, all sharing electrons.
When they go into water, they let go of H⁺ ions.

Oxoacids

usually have one predictable positive charge

Main group metal ions

can have multiple positive charges that must be specified.

Transitional metal ions

• Identify the nonmetal element.

• Remove the ending (usually “-ine” or “-gen”) to get the root.

• Add “-ide” at the end.

Non-metal anions

 use the name plus Roman numerals for the charge

Transitional metals

just use the name.

Main group metals

two nonmetals.
First element + prefix if needed, second element + -ide + prefix

Binary molecular compounds

Hydrogen Carbonate or Bicarbonate

HCO^-₃

Hydrogen Phosphate

HPO₄^2-

Hydrogen sulfite or bisulfite

HSO₃^-

Hydroxide

OH^-

Hypochlorite

ClO^-

Nitrate

NO₃^-

Nitrite

NO₂^-

Perchlorate

ClO₄^-

Permanganate

MnO₄^-

Phosphate

PO₄^3-

Sulfate

SO₄^2-

Sulfite

SO₃^2-

Thiocyanate

SCN^-

Acetate

CH₃COO^-

Ammonium

NH₄⁺

Azide

N₃^-

Carbonate

CO₃^2-

Chlorate

ClO₃^-

Chlorite

ClO₂^-

Chromate

CrO₄^2-

Cyanide

CN^-

Dichromate

Cr₂O₇^2-

Dihydrogen phosphate

H₂PO₄^-

Disulfide

S₂^2-

atoms tend to want 8 electrons in their outer shell to be stable, like the noble gases.

Octet Rule

This is the distance between the nuclei of two bonded atoms the shorter the bond, the closer atoms are together. The more the amount of bonds, the stronger and shorter

Bond length

the stronger the bond the harder to break

Bond strength

The energy to break a bond.

Bond energy

when a molecule can be drawn in multiple ways by moving electrons (bonds or lone pairs) while keeping the atoms in the same positions, and the real molecule is a blend of these structures.

Resonance

when electrons are spread out over several atoms instead of being stuck between just two atoms, which often happens in molecules with resonance.

Delocalization 

how many chemical bonds exist between two atoms

Bond order

(number of resonance structures)/(total number of bonds between the two atoms in all resonance structures​)

Bond order

(number of bonds between the atoms?)/(number of shared electron pairs​)

Bond order

Valence electrons of atom−Nonbonding electrons (lone pairs)−Bonding electron/2

Formal charge

how the electrons in a molecule are “assigned” to each atom compared to a neutral atom.

Formal charge

It helps us figure out the most stable Lewis structure.

Formal charge

when a big atom has more than 8 electrons in its outer shell because it has extra “rooms” (orbitals) to hold them

Expanded octet

Which rule comes first? Octet rule or formal charge

Octet rule

an atom, molecule, or ion that has an unpaired electron.

Radical

when molecules have a lonely electron (radicals), small atoms that are happy with less than 8 electrons, or big atoms that can hold more than 8 electrons

Octet rule exceptions

theory that predicts the shape of molecules based on how electron pairs around the central atom repel each other.

VSEPR

2 electron pairs

Linear

3 electron pairs

Trigonal Planar

4 electron pairs

Tetrahedral

4 electron pairs and 1 lone pair

Trigonal planar

3 electron pairs and 1 lone pair

Bent

4 electron pairs and 2 lone pairs

Bent

5 electron pairs

Trigonal Bipyramidal

5 electron pairs and 1 lone pair

See-saw

5 electron pairs and 2 lone pairs

T-shaped

5 electron pairs and 3 lone pairs

Linear

6 electron pairs

Octahedral

6 electron pairs and 1 lone pair

Square pyramidal

6 electron pairs and 2 lone pairs

Square planar

Adding the number of atoms bonded to the central atom and lone pairs on central atom

Steric number

Based on steric number

Electron geometry

Based on bonds and lone pairs

Molecular shape

EG: Linear, MS:Linear

180

EG:Trigonal planar, MS:Trigonal planar

120

EG:Trigonal planar MS:Bent

<120

EG:Tetrahedral MS:Tetrahedral

109.5

EG:Tetrahedral MS:Trigonal pyramidal

~107

EG:Tetrahedral MS:Bent

~104.5

EG:Trigonal bipyramidal MS:Trigonal bipyramidal

90° (axial–equatorial), 120° (equatorial–equatorial), 180

EG:Trigonal Bipyramidal MS:See-saw

<90°, <120°, <180°

EG:Trigonal bipyramidal MS:T-shaped

<90°, 180°

EG:Trigonal Bipyramidal MS:Linear

180

EG:Octahedral MS:Octahedral

90,180

EG:Octahedral MS:Square pyramidal

<90,<180

EG:Octahedral MS:Square planar

90,180

when the pulls of electrons in a molecule don’t cancel out, making one side slightly negative and the other slightly positive

Net dipole

molecules that have the same chemical formula but different arrangements of their atoms, giving them different shapes or properties

Isomers

These are like mirror or rotated versions of the same structure — the atoms are connected the same way, but they point in different directions in space

Stereoisomers

These are mirror-image twins that can’t be stacked on top of each other — like your left and right hands

Enantiomers

stereoisomers that are not mirror images of each other.

Diastereomers

the same molecule shown in different rotations around single bonds.

Conformers

These have the same bonds but different sides or positions across a double bond or ring.

Cis-trans isomers

have the same formula but different connections between atoms

Constitutional isomers

differ in the structure of the carbon chain

Chain isomers

have the same chain but the important group is in a different position

Positional isomers

Same atoms, but the type of group is different — like one molecule being an alcohol and another being an ether

Functional isomers

hydrocarbons with only single bonds between carbons, making them saturated and simple molecules that follow the formula CₙH₂ₙ₊₂.

Alkanes