A Simple Atomic Model and Separation Techniques

A comprehensive vocabulary review of GCSE chemistry and physics atomic structure fundamentals, including subatomic particles, atomic models, isotopes, relative atomic mass calculations, and mixture separation methods.

Hydrogen

A chemical element composed of only one type of atom, classified as an element rather than a compound or mixture.

Mixture of Compounds

A physical combination containing two or more distinct chemical compounds that are not chemically bonded together.

Mixture of Elements

A physical combination consisting of two or more different elements present in the same space without being chemically joined.

Plum Pudding Model

An early model of atomic structure developed after atoms were thought to be indivisible spheres, depicting the atom as a ball of positive charge with negative electrons embedded within it.

Discovery Order of Subatomic Particles

The chronological sequence in which subatomic particles were identified: electrons were discovered earliest, followed by protons, and neutrons were discovered latest.

Tennessine ($\text{Ts}$)

A synthetic chemical element with an atomic number of $117$ located in Group $7$ of the periodic table, possessing $7$ electrons in its outer shell.

Scientific Peer Review and Replication

The process by which discoveries made by a small group of scientists (such as the identification of tennessine in $2010$) must be independently tested, repeated, and verified before being officially accepted by the broader scientific community (achieved in $2015$).

Relative Atomic Mass ($A_r$)

The weighted average mass of an element's isotopes relative to their abundances, calculated using the equation: $\frac{(\text{mass number} \times \text{percentage abundance of isotope A}) + (\text{mass number} \times \text{percentage abundance of isotope B})}{100}$.

Neutron

An uncharged subatomic particle located in the atomic nucleus that possesses approximately the same relative mass as a proton.

Relative Mass of Protons and Neutrons

The property that a proton and a neutron share the exact same relative mass value of $1$, unlike an electron which is significantly lighter.

Dinitrogen Monoxide ($\text{N}_2\text{O}$)

A chemical compound in which each individual molecule contains exactly $2$ nitrogen atoms and $1$ oxygen atom.

Isotopes

Atoms of the same chemical element that contain the same number of protons but different numbers of neutrons, leading to different mass numbers.

Chadwick's Experiments

Scientific experiments that provided experimental evidence proving the existence of uncharged neutrons inside the atomic nucleus, leading to a modern understanding of isotopes.

Filtration

A physical separation technique used to separate an insoluble solid substance, such as sand, from a liquid, such as water.

Fractional Distillation Apparatus

A laboratory assembly comprising an electric heater, flask, thermometer, condenser, and collection beaker, used to separate a mixture of miscible liquids with different boiling points.

Condenser

A glass cooling tube in distillation apparatus where cold water enters from the bottom and exits at the top to cool and condense hot vapors; the flowing water absorbs thermal energy, increasing in temperature.

Crystallisation

A separation method used to produce solid solute crystals (such as sodium chloride) from a solution by gently heating to evaporate the solvent until crystallization occurs, followed by cooling.

Atomic Number

The number of protons in the nucleus of an atom, which also equals the number of electrons in a neutral atom (for example, element Y with an atomic number of $9$ has $9$ electrons and $9$ protons).

Mass Number

The total sum of protons and neutrons located within the nucleus of an atom (for example, element Y with atomic number $9$ and mass number $19$ has $19 - 9 = 10$ neutrons).

Atomic Nucleus

The small, dense, positively charged central region of an atom that contains the protons and neutrons, around which electrons orbit in shells.

Lithium Atom (Element Z)

An atom defined by having $3$ protons, $3$ electrons, and $4$ neutrons, arranged with $2$ electrons in its inner shell, $1$ electron in its outer shell, and all protons and neutrons packed into the central nucleus.