1. Atom – the smallest unit of an element that displays the same properties as the element, for example, hydrogen.

Can We Help with Your Assignment?

Let us do your homework! Professional writers in all subject areas are available and will meet your assignment deadline. Free proofreading and copy-editing included.

2. Atomic number – The number of protons in the nucleus of an atom; for example, the atomic number for helium is 2.

3. Chemical formula – A short form used to represent a molecule; uses letters and numbers; only pure substances have chemical formulas; H2O is the chemical formula for water.

4. Chemical property – The ability of a substance to change or react and to form new substances when interacting with other substances, for example, zinc reacts with hydrochloric acid to produce hydrogen gas.

5. Chemical reaction – Any change that occurs when substances interact to produce new substances with new properties; changes in the chemical and physical properties of the pure substances let you know that a chemical reaction has occurred; when vinegar and baking soda are combined, they react to produce frothy bubbles.

6. Chemical symbol – A short form used to represent the name of an element; C is the chemical symbol for carbon.

7. Combustibility – The ability of a substance to catch fire and burn in air.

8. Compound – A pure substance that can be broken down into smaller parts using chemical properties; water and carbon dioxide are both examples of compounds; all parts of a compound will contain identical molecules; in distilled water, all parts will contain identical H2O molecules.

9. Conductivity – Describes how easily a substance lets heat or electricity move through it.

10. Decomposition – A kind of reactivity that can break down a substance into its parts; for example, water can be broken down into hydrogen and oxygen by decomposition.

11. Density – Describes how compact a substance is, and is calculated by dividing mass by volume or D = m/v.

12. Electron – A particle of an atom that surrounds the nucleus; has a charge of negative one.

13. Element – A pure substance that cannot be broken down into simpler parts by chemical methods; all the elements are listed on the Periodic Table; all of the particles in an element are identical, as shown in the element aluminum.

Digestive System Terms & Definitions

14. Family – A vertical column of elements in the periodic table also known as a group.

15. Lustre – The ability to reflect light, or shine; silver has a high lustre and is so popular for jewellery; sodium metal is also lustrous.

16. Matter – Anything that has mass and occupies space (volume).

17. Metal – Typically, an element that is solid at room temperature, shiny, malleable, ductile, and a good conductor; for example, aluminum, iron, and calcium.

18. Mixture – matter than can be separated into parts using differences in physical properties; saltwater is a mixture of salt and water.

19. Molecule – A type of particle that is made up of two or more atoms bonded together; carbon monoxide is an example of a molecule.

20. Neutron – Located in the nucleus of an atom, has no charge.

21. Nucleus – In chemistry, the charged center of an atom; contains the atoms protons and neutrons.

22. Period – A horizontal row of elements in the periodic table; for example, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, and argon make up period 3 of the periodic table.

23. Periodic Table – A system for organizing the elements into columns and rows, so that elements with similar properties are in the same column.

24. Physical property – The way matter looks, feels, smells or tastes; one physical property of gold is its lustre.

25. Precipitation – A solid substance that can form when certain dissolved substances are mixed together.

26. Proton – A particle of an atom that is inside the nucleus; has a positive charge.

27. Pure substance – A substance made up of only one kind of matter; for instance, copper, distilled water and aluminum are all pure substances.

28. Solubility – Describes how much of a substance dissolves in another substance.

29. Texture – Describes how the surface of a substance feels (its roughness, softness, or smoothness).