Chemistry 11 Semester 1 Review

Vocabulary-style flashcards covering the key chemical concepts, history of the atom, mass spectrometry, periodic trends, bonding, and energy changes from the Chemistry 11 Semester 1 review.

John Dalton

Scientist who proposed the Solid Sphere Model in 1803, stating that atoms are indivisible, atoms of a given element are identical, and compounds are combinations of different types of atoms.

J.J. Thomson

Scientist who discovered electrons (corpuscles) in 1897 and proposed the "plum pudding" model, which shows electrons scattered throughout a spherical cloud of positive charge.

Ernest Rutherford

Scientist who performed the gold foil experiment and realized positive charge was localized in the nucleus, concluding that the atom was mostly empty space.

Niels Bohr

Scientist who proposed the Planetary Model in 1913, stating that electrons move around the nucleus in orbits of fixed sizes and energies (quantised).

Erwin Schrödinger

Scientist who proposed the Quantum Model in 1926, stating that electrons move in waves and reside in "clouds of probability" called orbitals where their position is uncertain.

Chadwick

Scientist who bombarded Beryllium with alpha particles from the natural radioactive decay of Polonium.

Mass number

The total number of neutrons plus protons in the nucleus of an atom.

Strong nuclear force

The force of attraction that exists between neutrons and protons in the nucleus.

Isotopes

Variations in mass number (neutrons) for atoms of the same element (same atomic number), possessing the same chemical properties but different physical properties.

Relative mass

The mass of an atom or molecule calculated relative to the mass of carbon 12.

Mass Spectrometry

A technique used to obtain data on the mass and abundance of isotopes by separating particles based on their mass/charge ratio.

Ionisation (Mass Spectrometry)

The stage where positive ions are formed as the vapour passes through a high energy electron beam.

Deflection (Mass Spectrometry)

The stage where a magnetic field deflects ions based on mass and charge; ions with a smaller mass and greater charge are deflected more.

Photon

The energy released when an excited electron returns to a lower state, where the amount of energy absorbed equals the energy released as a specific wavelength.

Atomic Absorption Spectroscopy

An analytical technique that detects a particular metal and determines its concentration by measuring absorbance against standard solutions.

Atomic radius

The distance from the nucleus to the outer electrons; it decreases across a period and increases down a group.

Electronegativity

The ability of an atom to attract electrons from other atoms; it increases across a period and decreases down a group.

Ionisation Energy

The amount of energy needed to remove an electron from an atom; it increases across a period and decreases down a group.

Nanomaterials

Particles with at least one dimension ranging from $1-100\,\text{nm} (\times 10^{-9})$, whose physical properties differ from the bulk material.

Metallic Bonding

A non-directional bond involving a lattice of positive metal ions surrounded by a sea of delocalised electrons.

Ionic Bonding

Bonding between non-metals and metals consisting of a lattice of alternating positive and negative ions held together by strong attractive forces.

Covalent Molecular Bonding

Bonding between non-metal atoms that share electrons to become stable, characterized by weak intermolecular forces and low melting points.

Covalent Network Bonding

Bonding where covalent bonds extend throughout a lattice (e.g., diamond or silicon dioxide), resulting in very high melting points and extreme hardness.

Allotropes

Different structural modifications of an element where atoms are bonded together in a different manner, resulting in different properties.

Mole

A unit of measurement representing $6.022 \times 10^{23}$ particles.

Saturated Compounds

Organic compounds such as Alkanes with single carbon-carbon bonds that typically undergo substitution reactions.

Unsaturated Compounds

Organic compounds such as Alkenes with double or triple carbon-carbon bonds that undergo addition reactions.

Exothermic

A reaction that releases energy as heat ($\text{Negative } \Delta H$), causing the temperature of the surroundings to increase.

Endothermic

A reaction that absorbs heat energy ($\text{Positive } \Delta H$), causing the temperature of the surroundings to decrease.

Biofuel

A fuel produced from living matter, obtained from renewable sources, and which is biodegradable and produces lower $CO_2$ emissions than fossil fuels.

Fossil Fuel

A naturally occurring fuel formed from geological processes over time, obtained primarily from non-renewable sources like mining or drilling.