Science 10 Chemistry - Classification of Matter and Atomic Structure

Flashcards covering the key concepts related to the classification of matter, atomic structure, and associated models in chemistry.

What is a pure substance?

Matter with fixed composition and properties.

Give an example of an element.

O₂ (oxygen) or C (carbon).

What is a compound?

Chemically bonded elements, e.g., H₂O (water) or NaCl (table salt).

What is the definition of a mixture?

Physically combined substances with variable composition.

Describe homogeneous mixtures.

Uniform mixtures, e.g., saltwater.

Describe heterogeneous mixtures.

Non-uniform mixtures, e.g., sand + iron filings.

What charge does a proton have?

Positive charge; defines atomic number (Z).

What role does a neutron play in an atom?

Contributes to atomic mass (A = Z + n); has no charge.

What is the charge of an electron?

Negative charge; occupies orbitals.

What was the key idea of Dalton’s Solid Sphere model?

Atoms are indivisible spheres.

What did Thomson’s Plum Pudding model propose?

Electrons are embedded in a positive 'pudding' with no nucleus.

What did Rutherford’s Nuclear Model introduce?

A dense nucleus with orbiting electrons based on the gold foil experiment.

What is the fundamental flaw of the Bohr’s Planetary Model?

Electrons should lose energy and collapse into the nucleus.

What does Schrödinger’s equation describe?

Electrons as probability waves.

What is the Aufbau Principle?

Fill orbitals from lowest to highest energy.

What are the valence electrons?

Outermost s/p electrons that determine bonding.

What is the Octet Rule?

Atoms gain/lose/share electrons to achieve 8 valence electrons, stable like noble gases.

What do ionic bonds involve?

Electrons donated by metals to non-metals.

What distinguishes polar covalent bonds?

Unequal sharing of electrons, ΔEN > 0.4.

What are hydrogen bonds?

Strong dipole-dipole interactions involving H bonded to F, O, or N.

What unique property of water is due to hydrogen bonding?

High boiling point and ice floats.

What is the hydrophobic effect?

Non-polar molecules cluster in water to minimize disruption of hydrogen bonds.

Compare the Bohr model and Quantum Mechanical model regarding electron location.

Bohr: Fixed orbits; Quantum: Probability clouds.