Chemistry Exam Grade 11 Review

A total overview of grade 11 Chemistry for Exam Preparation

What changed in the development of the atom from Dalton to Bohr?

Dalton → indivisible sphere; Thomson → electrons exist (plum pudding); Rutherford → nucleus discovered; Bohr → electrons in energy levels.

Which experiment proved atoms are mostly empty space?

Rutherford Gold Foil experiment.

Which atomic model cannot explain spectra?

Rutherford's model.

What is Bohr’s biggest limitation?

It only works well for hydrogen.

What is the formula for Average Atomic Mass?

[ \text{Average Mass}=\sum (\text{fraction})(\text{isotope mass}) ]

Calculate Average Atomic Mass of chlorine: 75% Cl-35 and 25% Cl-37.

[ (.75)(35)+(.25)(37)=35.5 ] Trap: Atomic mass ≠ mass number.

Why does atomic radius decrease across a period?

More protons → higher effective nuclear charge (Z_eff) → stronger attraction.

Why does atomic radius increase down a group?

More shells → increased shielding.

Lewis Dot Diagram Steps?

1. Count valence electrons; 2. Create skeleton; 3. Add single bonds; 4. Complete octets; 5. Use double/triple bonds if needed.

What are the exception atoms for the octet rule?

H → 2, Be → 4, B → 6.

What is expanded octet?

Atoms in Period 3 and beyond can have more than 8 electrons.

What is VSEPR and typical bond angles for different geometries?

• 2 VP → Linear → 180°; - 3 VP → Trigonal planar → 120°; - 4 VP → Tetrahedral → 109.5°.

Describe the polarity conditions for a molecule.

Polar bonds + asymmetry lead to a polar molecule.

Which is more polar, HF or HCl?

HF is more polar than HCl.

What are the intermolecular forces listed from weak to strong?

LDF < Dipole-Dipole < Hydrogen Bond < Ion-Dipole.

What is the highest boiling point condition?

The strongest intermolecular force present.

Why does water have a high boiling point?

Extensive hydrogen bonding.

Describe the nomenclature for ionic compounds.

Metal + nonmetal; Roman numeral if metal has variable charge (e.g., FeCl₃ = Iron(III) chloride).

Write the reaction types for the following: Synthesis, Decomposition, Single displacement, Double displacement, Combustion.

Synthesis: A+B→AB; Decomposition: AB→A+B; Single displacement: A+BC→AC+B; Double displacement: AB+CD→AD+CB; Combustion: hydrocarbon + O₂.

How to calculate % Yield?

[ \text{% Yield}=\frac{actual}{theoretical}\times100 ]

What does KMT state about gas particles?

They are in random motion, elastic collisions, and have negligible volume.

What is the ideal gas law formula?

[ PV=nRT ]

Calculate the total pressure from partial pressures.

[ P_T=P_1+P_2+… ]

What happens during a double displacement reaction?

Ions exchange partners to form new compounds.

What is the formula to convert moles to grams?

[ n=\frac{m}{M} ].

What is the pH formula?

[ pH=-\log[H^+] ].

Which compounds are strong acids?

Strong acids dissociate completely in water, resulting in low pH.