Science Lecture Notes: Atomic Structure, Separation, Bonding, and Reactivity

VOCABULARY flashcards based on lecture notes covering atomic structure, chemical models, mixtures and separation techniques, periodic table trends, bonding types, nanotechnology, acids, bases, and metal reactivity.

Isotopes

Atoms of an element with the same numbers of protons and electrons but different numbers of neutrons.

Atomic number

The number of protons in an atom of an element.

Mass number

The total number of particles (protons and neutrons) in the nucleus of an atom.

Relative mass of a proton

$$1$$

Relative mass of a neutron

$$1$$

Relative mass of an electron

Almost zero

Relative charge of a proton

$$+1$$

Relative charge of a neutron

Zero

Relative charge of an electron

$$-1$$

Radius of an atom

Approximately $1.0 \times 10^{-10}\,m$

Radius of a nucleus

Approximately $1.0 \times 10^{-14}\,m$, which is $10,000$ times smaller than the atomic radius.

Dalton’s Atomic Theory

The solid sphere model; atoms of different elements have different weights.

Plum pudding model

Thomson's theory that atoms contain negatively-charged electrons in a sphere that is otherwise positively-charged.

Gold foil experiment

Rutherford shot alpha particles at a $1$-atom thick piece of gold foil; most passed through but some deflected, leading to the discovery of the positive nucleus.

Bohr's Atomic Model

Electrons orbit the nucleus in energy levels (shells), with those having the least energy orbiting closest to the nucleus.

Chadwick's discovery

Discovered that the nucleus contains neutrons in addition to protons.

Element

A substance made of only one type of atom.

Compound

A substance made of different types of atoms that are chemically bonded.

Mixture

Different types of substances that are not chemically bonded.

Molecule

A particle made of two or more atoms bonded together.

Soluble

A substance that can dissolve.

Insoluble

A substance that cannot dissolve.

Saturated solution

A solution that has the maximum amount of solute dissolved.

Formulation

A mixture of specific ingredients designed as a useful product, such as medicines, fuels, or cosmetics.

Filtration

A method to separate an insoluble solid from a liquid because the solid (residue) cannot fit through the gaps in the filter paper.

Crystallisation

Separating a dissolved solute from a solution by evaporating the solvent.

Distillation

Separating a mixture of two liquids with different boiling points by evaporating and then condensing the liquid with the lower boiling point.

Paper chromatography

A separation technique involving a mobile phase (solvent) and a stationary phase (paper).

Rf value

A value calculated to compare spots on chromatograms using the formula: $Rf = \frac{\text{distance travelled by component}}{\text{distance travelled by the solvent}}$.

Pure substance

In chemistry, a substance that only contains a single element or compound and melts/boils at fixed temperatures.

Sublimation

The process where a solid changes directly into a gas when heated.

Deposition

The process where a gas forms a solid when cooled.

Aqueous solution

A substance dissolved in water, denoted by the state symbol $(aq)$.

Group (Periodic Table)

Vertical columns indicating the number of electrons in the outer energy level of an atom.

Period (Periodic Table)

Horizontal rows indicating the number of energy levels in an atom.

Noble gases (Group 0)

Unreactive elements with full outer electron energy levels.

Alkali metals (Group 1)

Soft, low-density, very reactive metals whose reactivity increases down the group.

Halogens (Group 7)

Non-metal elements whose reactivity decreases down the group; they form halide compounds with metals.

Ionic bond

A bond formed by electron transfer between a metal atom (losing electrons) and a non-metal atom (gaining electrons).

Giant ionic lattice

A structure of positive and negative ions with strong electrostatic forces of attraction between them.

Covalent bond

A shared pair of electrons between non-metal atoms.

Polymers

Simple covalent substances consisting of very large molecules.

Metallic bonding

A structure consisting of positive metal ions in layers surrounded by a "sea" of delocalised electrons.

Malleable

The property of metals that allows layers of ions to slide past each other easily without breaking.

Nanoparticles

Structures between $1$ and $100\,nm$ in diameter, consisting of a few hundred atoms.

Graphene

A single layer of graphite that is one atom thick, transparent, lightweight, and conducts electricity.

Carbon nanotubes (CNTs)

Cylindrical fullerenes made of rolled-up graphene that are very strong.

Buckminsterfullerene

A simple covalent molecule consisting of $60$ carbon atoms ($C_{60}$).

Alkali

A base that produces hydroxide ions $(OH^-)$ in aqueous solutions.

Strong acid

An acid that fully ionises in water to release many $H^+$ ions, such as hydrochloric, nitric, or sulfuric acids.

Neutralisation

A reaction between an acid and a base (metal oxide, hydroxide, or carbonate) to produce a salt and water.

Ionic equation for neutralisation

$$H^+ + OH^- \rightarrow H_2O$$

Oxidation

Gaining oxygen in a reaction or losing electrons (OIL).

Reduction

Losing oxygen in a reaction or gaining electrons (RIG).

Ores

Rocks containing enough of a metal compound to make extraction economical.

Rusting

The corrosion of iron in the presence of oxygen and water to form hydrated iron(III) oxide.

Galvanising

A type of sacrificial protection where iron is covered with a layer of zinc.

Sacrificial protection

Attaching a more reactive metal to iron so that the more reactive metal corrodes instead.