12.1 Basics of Chemistry: Matter, Elements, Atoms, Molecules & Compounds
Key Takeaways
- Matter is anything that occupies space and has mass; a physical change alters form without creating a new substance, while a chemical change creates a new substance and polymerisation is irreversible.
- An element is the simplest form of matter, an atom is its smallest particle, and a compound is a molecule containing atoms of two or more different elements in definite proportions.
- A solution is stable and does not separate, a suspension separates on standing — which is why nail lacquer is rolled rather than shaken — and an emulsion holds immiscible liquids together with a surfactant.
- pH applies only to water-based solutions, is logarithmic so each whole number is a tenfold change, and skin and nail sit at roughly pH 4.5 to 5.5.
- Acetone flashes at about minus 4 degrees Fahrenheit and isopropyl alcohol at about 53 degrees Fahrenheit, so an ignitable vapour layer is present above an open container at room temperature.
Basics of Chemistry: Matter, Elements, Atoms, Molecules and Compounds
Ohio State Board Exam Alert: The Board's blueprint devotes 10 % of the theory examination to Product Knowledge & Chemistry and lists the primitives individually: chemical reactions, matter, elements, atoms, molecules, compounds, adhesions, monomer/polymer. Ohio's 200-hour curriculum also names "chemistry basics" under General Sciences. These are definitional questions with unambiguous answers — free marks for anyone who learns the vocabulary.
Nail technology is applied chemistry. Every product on the station is a mixture of substances chosen for how they behave, and almost every service failure — lifting, service breakdown, discolouration, sensitisation — is a chemistry failure.
1. Matter and Its States
Chemistry is the science that deals with the composition, structure and properties of matter and how matter changes under different conditions. Matter is any substance that occupies space and has mass. Everything you touch at the nail station is matter; energy — heat, light, the UV output of a curing lamp — is not.
| State | Definite volume? | Definite shape? | At the nail station |
|---|---|---|---|
| Solid | Yes | Yes | Polymer powder, a cured enhancement, an abrasive file |
| Liquid | Yes | No | Monomer, acetone, cuticle oil, disinfectant solution |
| Gas | No | No | Solvent vapour rising from an open dappen dish |
Two distinctions carry marks:
- Physical change vs chemical change. A physical change alters form without creating a new substance — ice melting, acetone evaporating, a file abrading a plate. A chemical change creates a new substance with new properties — monomer polymerising into a hard enhancement, or bleach oxidising organic matter. Polymerisation is a chemical change and is irreversible, which is why a cured enhancement cannot be melted back into monomer.
- Physical property vs chemical property. Physical properties are observable without changing the substance's identity: colour, odour, density, melting point, solubility. Chemical properties describe how a substance reacts: flammability, ability to oxidise, ability to polymerise.
2. Elements and Atoms
An element is the simplest form of matter, which cannot be broken down into a simpler substance without loss of identity. There are just over one hundred, each with a chemical symbol. The five that dominate nail work:
| Element | Symbol | Why it matters |
|---|---|---|
| Carbon | C | Backbone of every organic molecule in nail products |
| Hydrogen | H | The lightest element; in water, solvents and every organic compound |
| Oxygen | O | In water and in the ester groups of methacrylates; inhibits surface cure, producing the tacky inhibition layer on gels |
| Nitrogen | N | In the amino acids of keratin |
| Sulphur | S | The element behind the disulphide bonds that make hard keratin hard |
An atom is the smallest particle of an element that still has the properties of that element. Atoms are the building blocks: elements are made of one kind of atom, and compounds are made of atoms of different elements bonded together.
3. Molecules and Compounds
A molecule is a chemical combination of two or more atoms in definite proportions.
- Elemental molecules contain two or more atoms of the same element — oxygen gas, O₂; nitrogen gas, N₂.
- Compound molecules — usually just called compounds — contain atoms of two or more different elements in definite proportions: water H₂O, hydrogen peroxide H₂O₂, sodium chloride NaCl, acetone C₃H₆O.
Water and hydrogen peroxide illustrate why proportion is part of the definition. Both are made only of hydrogen and oxygen, but H₂O is the universal solvent and H₂O₂ is an oxidising antiseptic. One extra oxygen atom completely changes the substance.
4. Mixtures, Solutions, Suspensions and Emulsions
Matter that is not chemically combined is a physical mixture — a combination of two or more substances that keep their own identities and can be separated by physical means.
| Mixture type | Description | Nail-station example |
|---|---|---|
| Solution | A uniform, stable blend of a solute dissolved in a solvent; does not separate on standing | Salt in water; a nail dehydrator; bleach diluted 1:9 for disinfection |
| Suspension | Larger particles distributed in a liquid; unstable and separates on standing | Nail lacquer with pigment settled at the bottom — the reason polish is rolled, never shaken |
| Emulsion | Two immiscible liquids held together by an emulsifier / surfactant | Hand lotion and massage cream (oil in water) |
Miscible liquids mix into a stable solution; immiscible liquids separate. Oil and water are immiscible, which is why a lotion needs a surfactant with a water-loving (hydrophilic) head and an oil-loving (lipophilic) tail to bridge them — and why the same surfactant chemistry, in soap, lifts oil and soil off implements before disinfection.
Practice point: shaking a bottle of nail lacquer whips air into the suspension, producing bubbles that show up as pits in the cured surface. Roll the bottle slowly between the palms to redistribute the pigment without aeration.
5. pH and the Acid Mantle
pH measures the acidity or alkalinity of a water-based solution on a logarithmic scale from 0 to 14, where 7 is neutral. Below 7 is acidic, above 7 is alkaline. Because the scale is logarithmic, each whole number is a tenfold change: pH 5 is ten times more acidic than pH 6 and one hundred times more acidic than pH 7.
- Skin and nail sit at roughly pH 4.5 to 5.5 — the acid mantle formed by sebum and sweat, which suppresses microbial colonisation.
- Alkaline products swell and soften keratin. Cuticle removers containing potassium or sodium hydroxide work by raising pH to break down dead tissue; left on too long they irritate living skin, which is why contact time matters.
- Products with no water have no pH. Monomer, acetone and anhydrous oils are non-aqueous, so it is meaningless to describe them as acidic or alkaline. Nail "acid primers" are named for the methacrylic acid they contain, not for a pH reading.
6. Vapours, Fumes and Why the Distinction Matters
| Term | Correct meaning |
|---|---|
| Vapour | Molecules that have evaporated from a liquid at room temperature — monomer, acetone, solvent |
| Fume | Fine solid particles produced by combustion or high heat — welding fume |
| Dust | Solid particles produced mechanically by filing, grinding or abrading |
| Mist | Fine liquid droplets suspended in air — an aerosol spray |
Salons do not produce fumes; they produce vapours and dust. The distinction is not pedantry — it determines the control. Vapours require ventilation and, where needed, a chemical cartridge respirator; a dust mask does nothing at all against vapour. Dust requires source capture and a particulate respirator. Getting the terminology right is how a technician chooses the right protection.
7. Volatility, Flash Point and Storage
Volatile organic compounds (VOCs) evaporate readily at room temperature. Acetone, ethyl acetate, isopropyl alcohol and monomer are all volatile, and all are flammable.
Flash point is the lowest temperature at which a liquid gives off enough vapour to ignite in the presence of an ignition source. Acetone's flash point is about −4 °F (−20 °C) and isopropyl alcohol's about 53 °F (12 °C) — both far below room temperature, meaning an ignitable vapour layer is present above an open container at all times.
Practical consequences: keep containers closed when not in use, store away from heat, towel steamers, curing lamps and direct sunlight, use a covered dappen dish and a metal, self-closing waste container for solvent-soaked materials, and remember that vapour is heavier than air and pools at bench level where you are breathing.
A technician shakes a bottle of nail lacquer vigorously before applying it, and the finished manicure shows small pits across the surface. What is the chemistry behind the fault?
Which statement correctly applies chemistry vocabulary to the nail station?
Why is polymerisation classified as a chemical change rather than a physical change?