General Chemistry Fundamentals

What are the three subatomic particles?

Protons (+), neutrons (0), and electrons (−).

Where are protons and neutrons located?

In the nucleus.

Where are electrons located?

In the electron cloud surrounding the nucleus.

What determines an element's identity?

The number of protons (atomic number).

What is the atomic number?

The number of protons.

What is the mass number?

Protons + neutrons.

What are isotopes?

Atoms of the same element with different numbers of neutrons.

What is an ion?

An atom that has gained or lost electrons.

What is a cation?

A positively charged ion.

What is an anion?

A negatively charged ion.

Which direction does atomic radius increase?

Down and to the left.

Which direction does ionization energy increase?

Up and to the right.

Which direction does electronegativity increase?

Up and to the right.

Which group contains the alkali metals?

Group 1.

Which group contains the alkaline earth metals?

Group 2.

Which group contains the halogens?

Group 17.

Which group contains the noble gases?

Group 18.

What is the maximum number of electrons in the first energy level?

2

What is the maximum number of electrons in the second energy level?

8

What are valence electrons?

Electrons in the outermost shell.

Why are valence electrons important?

They determine chemical properties and bonding.

What is an ionic bond?

Transfer of electrons between a metal and a nonmetal.

What is a covalent bond?

Sharing of electrons between nonmetals.

What is a metallic bond?

Positive metal ions surrounded by a sea of mobile electrons.

Which bond is usually stronger: ionic or intermolecular forces?

Ionic bonds.

What does a Lewis structure show?

Valence electrons and bonding.

What determines molecular shape?

Repulsion between electron pairs (VSEPR).

What is a polar molecule?

A molecule with an uneven distribution of charge.

What is a nonpolar molecule?

A molecule with an even distribution of charge.

What is the weakest intermolecular force?

London dispersion forces.

Which intermolecular force occurs between all molecules?

London dispersion forces.

What causes dipole-dipole forces?

Attraction between polar molecules.

What is hydrogen bonding?

Strong attraction when H is bonded to N, O, or F.

Which intermolecular force is strongest?

Hydrogen bonding.

What is one mole?

6.022 × 10²³ particles.

What is Avogadro's number?

6.022 × 10²³

How do you calculate molar mass?

Add atomic masses from the periodic table.

How do you convert grams to moles?

Divide by molar mass.

How do you convert moles to grams?

Multiply by molar mass.

What must be done before solving any stoichiometry problem?

Balance the chemical equation.

What is the limiting reactant?

The reactant that runs out first.

What is excess reactant?

The reactant left over.

What is theoretical yield?

Maximum amount of product possible.

What is actual yield?

Amount of product actually obtained.

Formula for percent yield?

(Actual ÷ Theoretical) × 100%

What is a synthesis reaction?

Two substances combine to form one product.

What is a decomposition reaction?

One compound breaks into simpler substances.

What is a combustion reaction?

A substance reacts with oxygen, usually producing CO₂ and H₂O.

What is a single replacement reaction?

One element replaces another.

What is a double replacement reaction?

Ions exchange partners.

What is STP?

0°C and 1 atm.

Molar volume of a gas at STP?

22.4 L/mol.

Ideal Gas Law?

PV = nRT.

Boyle's Law?

Pressure and volume are inversely related.

Charles's Law?

Volume and temperature are directly related.

What temperature scale is used in gas laws?

Kelvin.

What is molarity?

Moles of solute per liter of solution.

Formula for molarity?

M = moles ÷ liters.

What happens during dilution?

Volume increases while moles stay the same.

Dilution formula?

M₁V₁ = M₂V₂.

What is an endothermic reaction?

Absorbs heat.

What is an exothermic reaction?

Releases heat.

What is specific heat?

Heat needed to raise 1 g by 1°C.

Heat equation?

q = mcΔT.

What is enthalpy (ΔH)?

Heat change at constant pressure.

What is the pH of a neutral solution?

7

What is the pH of an acid?

Less than 7.

What is the pH of a base?

Greater than 7.

Strong acids completely __ in water.

Dissociate.

Strong bases completely __ in water.

Dissociate.

What is oxidation?

Loss of electrons.

What is reduction?

Gain of electrons.

What mnemonic helps remember redox?

OIL RIG (Oxidation Is Loss, Reduction Is Gain).

How many significant figures are in 0.00450?

3

Why are significant figures important?

They show the precision of measurements.