| A | B |
|---|
| matter | anything that occupies space and has mass |
| properties of matter | physical: the ones you can observe without changing the matter's chemicla composition. size, shape, texture, hardness |
| volume | the amount of space occupied by matter |
| mass | the amount of matter in an object |
| density | the ratio of matter's mass to it's volume |
| what is the physical state of matter? | the form in which it exists |
| element | a substance that cannot be broken down by chemical processes into simpler substances |
| atom | the smallest particle of an element that has the properties of the element |
| compound | two or more different elements liked chemically in definate proportions |
| protons | particles with a relatively large mass and a positive charge |
| neutrons | particles with about the same mass as protons and no charge |
| electrons | particles with a relatively small mass and a negative charge |
| similarities between protons and neutrons, diff w/ elect | both located in nucleus of each atom, but electrons move in large, definate space outside of nucleus. p's and n's have masses 2000x greater than electrons |
| energy levels | the regions in which electrons move, called this because the electrons in different regions have different amounts of energy |
| first energy level can hold max of how many electrons? | 2 |
| 2nd energy level can hold max of how many electrons? | 8 |
| 3rd energy level can hold max of how many electrons? | 18 |
| fourth energy level can hold max of how mnay electrons? | 32 |
| the outermost level of any atom never actually holds more than how many? why? | 8. stability arrangement |
| atomic number | the number of protons in an element |
| mass number | the number or protons plus neutrons in an element |
| isotopes | atoms of the same element that have the same number of protons but different numbers of neutrons, in an element |
| radioactive isotopes | the nucleus is unstable and breaks apart spontaneously. when they break apart, they give off energy |
| do all atoms of the same element have the same number or different number of protons? | same number |
| what information about elements is in the periodic table? | what elementis have smiliar chemical properties, the atomic number of the element, the element symbol, the average atomic mass |
| average atomic mass | the average of the masses of the isotopes |
| ionic bond | forms when ions with opposite charges are attracted to each other |
| ions | atoms formed when atos gain or lose electrons, forming positively or negatively charged atoms |
| when can ionic bonds break? | when they are placed in water |
| covalent bonds | form when atoms share electrons |
| only what part of electrons are involved in forming covalent bonds? | the outermost (highest) energy |
| how many covalent bonds are needed to hold two atoms together? | one or more |
| molecules | two or more atoms held together by covalent bonds |
| chemical reaction | a process in which substances are changed into new substances by the breaking and forming of chemical bonds |
| what does an arrow indicate in a chemical equation? | that a reaction is taking place |
| endothermic reactions | reactions in which energy is absorbed |
| exothermic reactions | reactions that release energy |
| solution | a uniform mixturte of two or more substances |
| solute | the dissolved substance in a solution |
| solvent | the dissolving substance in a solution |
| gas-gas solution example | air: carbon dioxide and oxygen in nitrogen |
| liquid-gas solution example | moist aire: water droplets in air |
| gas-liquid solution example | soda water: co2 in h20 |
| liquid-liquid solution example | vinegar: acetic acid in water |
| solid-liquid solution example | brine: sodium chloride in water |
| solid-solid | sterling silver: an alloy of copper in silver |
| what percent of the bodies of most organisms is water? | 65-95% |
| what is water in in our bodies? | saliva, digestive fluids, fluids that surround and protect our brain, and the liquid that cushoins a developing fetus |
| polar molecule and example | results when electrons are shared unequally between atoms. example: water |
| acid | a compound that releases hydrogen ions |
| hydrogen ion symbol | H+ |
| base | a compound that releases hydroxide ions |
| hydroxide ion symbol | OH- |
| salts | compounsd that release ions other than hydrogen or hydroxide ions |
| pH scale | a standard measurement of the concentration of hydrogen ions in a solution |
| number system of pH scale | 0-14, 0 being very acidic and 14 being very basic. 7 neutral. when pH goes from (EX) 6 to 5, concentration of hyd. ions increases 10 X |
