Across
- 5. A subatomic particle of about the same mass as a proton but without an electric charge, present in all atomic nuclei except those of ordinary hydrogen.
- 7. A variable that is intentionally changes to observe its effect on the dependent variable.
- 8. The extent to which a test accurately measures what it is supposed to measure.
- 11. A chemical bond formed between two ions with opposite charges.
- 12. A process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.
- 13. A particle smaller than an atom, or a cluster of such particles.
- 16. A type of chemical reaction in which two or more simple substances combine to form a more complex product.
- 17. Properties that describe how one substance reacts with another substance. Chemical properties may only be observed by reacting one chemical with another.
- 18. The total number of protons and neutrons in a nucleus.
- 24. The basic unit of a chemical element.
- 25. The law that states when elements are arranged according to their atomic number, physical and chemical properties repeat.
- 27. An element whose properties are intermediate between those of metals and solid nonmetals.
- 29. The mass of an atom of a chemical element expressed in atomic mass units. It is approximately equivalent to the number of protons and neutrons in the atom (the mass number) or to the average number allowing for the relative abundances of different isotopes.
- 30. A type of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products.
- 32. Characteristic of a substance that is observed during a reaction in which the chemical composition or identity of the substance is changed.
- 33. Tells us the number of atoms of each element in a compound.
- 34. An atom or molecule with a net electric charge due to the loss or gain of one or more electrons.
- 40. The symbolic representation of a chemical reaction in the form of symbols and formulae.
- 42. Elements that form cations when compounds of it are in solution and oxides of the elements form hydroxides rather than acids in water.
- 43. A chemical reaction that releases energy by light or heat. It is the opposite of an endothermic reaction.
- 46. Of or denoting a process involving substances in different phases (solid, liquid, or gaseous).
- 47. The group in an experiment or study that does not receive treatment by the researchers and is then used as a benchmark to measure how the other tested subjects do.
- 48. The number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.
- 52. One of the basic substances that are made of atoms of only one kind and that cannot be separated by ordinary chemical means into simpler substances.
- 53. All atoms want 8 valence electrons like the noble gases.
- 55. A proposition, or set of propositions, set forth as an explanation for the occurrence of some specified group of phenomena.
- 56. A multiplier or factor that measures some property.
- 57. A substance that takes part in and undergoes change during a reaction.
- 58. A substance that is formed as the result of a chemical reaction.
Down
- 1. One of the horizontal rows in the periodic table.
- 2. The positively charged central core of an atom, consisting of protons and neutrons and containing nearly all its mass.
- 3. A process or reaction in which the system absorbs energy from its surroundings.
- 4. Regions of space around the nucleus of an atom where an electron is likely to be found.
- 6. Type of chemical reaction in which a single compound breaks down into two or more elements or new compounds.
- 8. Something that may or does vary or change.
- 9. A stable subatomic particle occurring in all atomic nuclei, with a positive electric charge equal in magnitude to that of an electron, but of opposite sign.
- 10. Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.
- 14. Any factor that remains unchanged and strongly influences values; also, a factor held constant to test the relative impact of an independent variable.
- 15. Of the same kind; alike.
- 19. A negatively charged ion.
- 20. Occurs when the number of the different atoms of elements in the reactants side is equal to that of the products side.
- 21. A type of chemical reaction where one element replaces another element in a compound.
- 22. A usually reversible change in the physical properties of a substance, as size or shape.
- 23. A type of chemical bond involving the sharing of electrons between atoms in a molecule.
- 26. A positively charged ion, i.e., one that would be attracted to the cathode in electrolysis.
- 28. The state or quality of being dense; compactness; closely set or crowded condition.
- 31. Ion with more than one atom, has a charge, acts like a single unit.
- 33. An exothermic reaction in which something reacts with oxygen.
- 35. A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.
- 36. A usually irreversible chemical reaction involving the rearrangement of the atoms of one or more substances and a change in their chemical properties or composition, resulting in the formation of at least one new substance.
- 37. The event studied and expected to change when the independent variable is changed.
- 38. An element or substance that is not a metal.
- 39. An aspect of matter that can be observed or measured without changing it.
- 40. Energy stored in the bonds of chemical compounds (atoms and molecules).
- 41. Something made by combining two or more ingredients.
- 44. A lasting attraction between atoms that enables the formation of chemical compounds.
- 45. Sample of matter with both definite and constant composition with distinct chemical properties.
- 49. Substance formed when two or more chemical elements are chemically bonded together.
- 50. A variable that cannot be changed or is purposely not changed in an experiment.
- 51. A stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.
- 54. act or process of testing, a putting to proof by examination, experiment, etc.