Chemistry Notables

Chemistry Notables Level 1

3Intro to Chemistry

Science

- a branch of knowledge or study dealing with a body of facts or truths systematically arranged and showing the operation of general laws.

Chemistry

- the science that deals with the composition and properties of substances and various elementary forms of matter.

Chemical

- a substance produced by or used in a chemical process.

4Atom The smallest unit of matter. (Level 2) The smallest component of an element having the chemical properties of the element, consisting of a nucleus containing combinations of neutrons and protons and one or more electrons bound to the nucleus by electrical attraction; the number of protons determines the identity of the element.

5Atomic Number The number of positive charges or protons in the nucleus of an atom of a given element.

                                                                                                                                                                                                                                         

6Bond An attraction between atoms that forms chemical substances.

                                                                                                                                                                                                                                         

7Compound A pure substance composed of two or more elements whose composition is constant.

                                                                                                                                                                                                                                         

8Electron A negatively charged particle that orbits the nucleus of an atom.

                                                                                                                                                                                                                                         

9Element One of a class of substances that cannot be separated into simpler substances by chemical means.

                                                                                                                                                                                                                                         

10Ion An electrically charged atom or group of atoms formed by the loss or gain of one or more electrons.

                                                                                                                                                                                                                                         

11Isotope Any of two or more forms of a chemical element, having the same number of protons in the nucleus, or the same atomic number, but having different numbers of neutrons in the nucleus, or different atomic weights.

12Mass Number The integer nearest in value to the atomic weight of an atom and equal to the number of nucleons in the nucleus of the atom.

13Matter The substance of which a physical object is composed.

                                                                                                                                                                                                                                         

14Metal A substance that is a good conductor of heat and electricity. They are generally malleable, ductile, and shiny.

                                                                                                                                                                                                                                         

15Mixture A combination of two or more substances that are not chemically combined.

                                                                                                                                                                                                                                         

16Molecule The smallest physical unit of an element or compound, consisting of one or more like atoms in an element and two or more different atoms in a compound.

                                                                                                                                                                                                                                         

17Neutron An elementary particle having no charge, mass slightly greater than that of a proton.

                                                                                                                                                                                                                                         

18Solution A homogeneous, molecular mixture of two or more substances. (Level 2) the process by which a gas, liquid, or solid is dispersed homogeneously in a gas, liquid, or solid without chemical change.

                                                                                                                                                                                                                                         

19Solvent A substance that dissolves another to form a solution.

                                                                                                                                                                                                                                         

Chemistry Notables Level 2

20Acid A compound having a pH value of less than 7, usually having a sour taste and capable of neutralizing alkalis and reddening blue litmus paper.

                                                                                                                                                                                                                                         

21Alkali metals Any of the group of univalent metals including potassium, sodium, lithium, rubidium, cesium, and francium, whose hydroxides are alkalis.

                                                                                                                                                                                                                                         

22Alkaline earth metals The group of bivalent metals including barium, radium, strontium, calcium, and, usually, magnesium, the hydroxides of which are alkalis but less soluble than those of the alkali metals.

                                                                                                                                                                                                                                         

23Allotropes One of two or more existing forms of an element: Graphite and diamond are allotropes of carbon.

                                                                                                                                                                                                                                         

24Alloy A substance composed of two or more metals, or of metals with a nonmetal, intimately mixed, as by fusion or electrodeposition.

                                                                                                                                                                                                                                         

25Base Is the opposite of acid and has a pH of 7 to 14. Compounds that form hydroxyl ions (OH) when dissolved in water, and whose aqueous solutions have a bitter taste and react with acids to form salts. Bases turn red litmus paper blue.

                                                                                                                                                                                                                                         

26Chemical reaction A process where a set of substances undergo a chemical change to form a different substance.

                                                                                                                                                                                                                                         

27Covalent bond Occurs between atoms that share a pair of electrons in order to gain full outer shells.

                                                                                                                                                                                                                                         

28Density Density is the mass per unit volume of a substance.

                                                                                                                                                                                                                                         

29Distillation The process of separating mixtures by boiling a liquid and then recovering the cooled gas.

                                                                                                                                                                                                                                         

30Electrolysis A process used to drive a chemical reaction by using an electrical current. It is often used to separate elements.

                                                                                                                                                                                                                                         

31Noble gases A family of elements that makes up column 18 of the periodic table. They are very stable due to their full outer electron shells.

                                                                                                                                                                                                                                         

32Oxidation The name for the process when oxygen combines with another element to form a compound.

                                                                                                                                                                                                                                         

33PH scale Measures the activity of the hydrogen ion in substances. If a substance has a pH less than 7 it is said to be acidic. If its PH is greater than 7 then it said to be basic or alkaline.

                                                                                                                                                                                                                                         

34Radioactivity Or radioactive decay is a process in which an unstable nucleus loses energy by the emission of radiation in the form of a particle.

                                                                                                                                                                                                                                         

35Reaction The process that occurs when two or more chemical substances are combined to form another chemical substance.

                                                                                                                                                                                                                                         

36Salts Chemical compounds that are formed by the reaction of an acid and a base.

                                                                                                                                                                                                                                         

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