Chemistry Exam Review

Flashcards for reviewing key concepts in chemistry.

What is the goal concerning electron count for atoms in chemical bonding?

To achieve a full or completely empty outer electron shell, typically aiming for eight electrons.

Describe the relationship between Group 1 and Group 17 elements in terms of electron transfer.

Group 1 elements (+1 charge) tend to give electrons to Group 17 elements (-1 charge) to achieve a stable electron configuration.

What changes in isotopes, and how does it affect chemical properties?

Isotopes have a change in mass due to a varying neutron count which affects physical properties not chemical.

How does changing the number of electrons affect an atom?

Changing electrons alters the charge, influencing the atom's ability to attract or interact with other substances.

What are ions and how are they formed?

Ions are charged atoms formed by gaining (anions) or losing (cations) electrons.

How does changing the number of protons affect an atom?

Changing the number of protons changes the element itself.

What is the key relationship between grams and moles?

Molar mass is the key relationship between grams and moles

What is the key relationship between moles and number of particles?

Avogadro's number.

What key relationship does density provide?

Density is the key between mass and volume.

What key relationship does molarity provide?

Molarity is the key between moles and volume.

List the order of filling electron orbitals.

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s

Describe the trend in atomic radius on the periodic table.

Atomic radius increases from top to bottom (more electron shells) and decreases from left to right (increased nuclear charge).

Describe the trend in electronegativity on the periodic table.

Electronegativity increases from left to right and decreases from top to bottom.

What is ionization energy?

Ionization energy is the energy required to remove valence electrons NOT core electrons.

How does ionic radii change when negative ions are formed?

Negative ions are larger than neutral atoms because electrons are added.

Why does successive ionization energy increase?

Successive ionization energy increases due to a higher proton-to-electron ratio which means more attraction.

Describe covalent bonds.

Covalent bonds involve the sharing of electrons between nonmetals which creates valence shells that overlap.

Explain the relationship between bond length and strength for single, double, and triple bonds.

Triple bonds are the shortest and strongest, while single bonds are the longest and weakest.

Describe ionic bonding.

Ionic bonding: Metal to nonmetal which involves the give and take of electrons (redox).

Describe metallic bonding.

Metallic bonding consists of a sea of delocalized electrons that are free to move.

List the common polyatomic ions to memorize.

Sulfate, phosphate, carbonate, chlorate, acetate, nitrate, hydroxide, and ammonium (NH4+).

How do you calculate formula mass?

Formula mass is the sum of the atomic masses of all atoms in a formula.

What is the relationship between empirical and molecular formulas?

Molecular and empirical mass can be the same.

List the 5 types of reactions.

Synthesis, decomposition, combustion, single displacement, and double displacement.

What is a limiting reactant?

Limitng Yield(limiting reactant) limits the amount of product that can be formed in a reaction.

What is the formula for Percent yield?

Percent yield= actual yield/ theoretical yield x100.

What does Graham's Law of Effusion state?

Smaller gases travel faster and escape faster; bigger gases travel slower and escape slower.

What are the conditions for STP?

0 degrees Celsius and 1 atm.

What is the volume of 1 mol of any gas at STP?

22.4 L.

List the phase changes.

Freezing & melting, condensation & vaporization (boiling is a type of vaporization), sublimation (solid straight to gas), and deposition (gas straight to solid).

What are electrolytes and nonelectrolytes?

Electrolytes allow ions to dissolve while Non electrolytes do not.

How can you speed up dissolution?

Heating, stirring, and crushing in general can speed up dissolution.

What are the 3 types of saturation?

Unsaturated (not dissolved), saturated (dissolved all we can), and supersaturated (dissolved more than we should be able to at this temp).

How are molarity dilutions calculated?

M1V1=M2V2.

What is an electrolyte?

Electrolytes are weak acids and bases being weak electrolytes, strong being strong.

What is the Bronsted-Lowry acid-base theory?

Acids are proton donors, and bases are proton acceptors.

What is the formula for enthalpy?

q=mc delta T.

What are endothermic and exothermic reactions?

Endothermic reactions absorb heat (delta H > 0), while exothermic reactions release heat (delta H < 0).

What happens to temperature during endothermic reactions?

Temperature decreases during endothermic reactions since heat is being absorbed.

What happens to temperature during exothermic reactions?

Temperature increases during exothermic reactions since heat is released.