Terms : Hide Images
| 282140170 | element | a substance that cannot be broken down to other substances by ordinary chemical means | |
| 282140171 | matter | anything that occupies space and has mass | |
| 282140172 | compound | a substance consisting of two or more different elements combined in a fixed ratio | |
| 282140173 | trace element | essential to human health, but only in small quantities | |
| 282140174 | proton | a subatomic particle with a single positive electrical charge | |
| 282140175 | electron | a subatomic particle with a single negative charge | |
| 282140176 | neuron | a subatomic particle that is electrically neutral | |
| 282140177 | nucleus | an atom's central core, where the protons and electrons are located | |
| 282140178 | atomic number | the unique number of protons in the atom of a particular element | |
| 282140179 | mass number | the sum of the number of protons and neurons in the nucleus | |
| 282140180 | isotopes | have the same number of protons as the element, behave identically in chemical reactions, but have different numbers of neutrons | |
| 282140181 | radioactive isotope | isotope whose nucleus decays spontaneously, giving off particles and energy | |
| 282142401 | electron shells | certain energy levels at the nucleus that electrons move around | |
| 282142402 | chemical bonds | attractions that hold atoms close together | |
| 282142403 | covalent bond | the strongest kind of chemical bond, in which two atoms share one or more pairs of outer-shell electrons | |
| 282142404 | molecule | made up of two or more atoms held together by covalent bonds | |
| 282142405 | electronegativity | an atom's attraction for shared electrons | |
| 282142406 | nonpolar covalent bonds | bonds in which electrons are shared equally between the atoms | |
| 282142407 | polar covalent bonds | unequal sharing of electrons within a bond | |
| 282142408 | polar molecule | molecule that has an unequal sharing distribution of charges | |
| 282142409 | ionic bond | when opposite charges attract and hold together to form a bond | |
| 282147473 | salt | a synonym for an ionic compound | |
| 282147474 | hydrogen bond | a bond in which the positively charged region is always a hydrogen atom | |
| 282147475 | chemical reaction | the breaking and making of chemical bonds, leading to changes in the composition of matter | |
| 282147476 | reactants | the starting materials in a chemical reaction | |
| 282147477 | product | the material resulting from a chemical reaction | |
| 282147478 | cohesion | the tendency of molecules of the same kind to stick together | |
| 282147479 | adhesion | the clinging of one substance to another | |
| 282147480 | surface tension | a measure of how difficult it is to stretch or break the surface of a liquid | |
| 282147481 | heat | the amount of energy associated with the movement of atoms and molecules in a body of matter | |
| 282147482 | temperature | measures the intensity of heat or the average speed of molecules rather than the total amount of heat energy in a body of matter | |
| 282147483 | evaporative cooling | when a substance evaporates, the surface of the liquid that remains behind cools down | |
| 282147484 | solution | a liquid consisting of a uniform mixture of two or more substances | |
| 282147485 | solvent | the dissolving agent | |
| 282147486 | solute | the substance that is dissolved | |
| 282147487 | aqueous solution | a solution in which water is the solvent | |
| 282147488 | acid | a compound that donates hydrogen ions to solutions | |
| 282147489 | base | a compound that accepts hydrogen ions and removes them from solutions | |
| 282147490 | pH scale | describes how acidic or basic a solution is | |
| 282147491 | buffers | substances that minimize changes in pH within solutions | |
| 282147492 | acid precipitation | refers to rain, snow, or fog with a pH lower than 5.2 | |
| 282147493 | ocean acidification | CO2 dissolving in seawater lowers the ocean's pH because the CO2 reacts with carbonic acid |
