| A | B |
|---|
| Anything that has mass and takes up space. | Matter |
| Matter can be classified as: | Elements, compounds, mixtures |
| Two or more elements chemically combined in a fixed ratio form: | a compound |
| Atoms of any ______ are alike but are different from the atoms of any other ____ . | Element |
| An important group of compounds that contain hydrogen | Acids |
| When acids dissolve in water, ____________ are released into the resulting solution. | Hydrogen ions (H+) |
| A substance that releases hydroxide ions (OH-) into solution. | a base |
| A measure of the hydrogen ion concentration in a solution | pH |
| pH scale ranges from: | 0-14 |
| Solutions with a pH lower than 7 are: | Acidic |
| Solutions with a pH greater than 7 are: | Basic |
| A pH of 7 is: | Neutral |
| This is formed along with water when an acid reacts with a base? | A salt |
| Name seven physical properties of matter. | Shape, density, solubility, odor, melting point, boiling point, color |
| Which physical properties are characteristic of a substance and do not depend on the size of the sample? | Density, solubility and boiling point |
| Name 4 chemical properties of a substance. | Acidity, basicity combustibility, and reactivity |
| All organic compounds contain this. | Carbon |
| Building blocks of matter | Atoms |
| Model of the structure of the atom that does not depict the three dimensional aspect of an atom and implies that electrons are in static orbits. | The Bohr model. |
| Model that represents our current understanding of the structure of the atom. | The electron cloud |
| The number of elements | More than 110 |
| No element with an atomic number greater than this is found in measurable quantities on Earth. | 92 |
| Elements with atomic numbers over 92 are: | artificially produced in a laboratory setting |
| Elements combine in many ways to produce ____ that make up all substances on Earth. | compounds |
| A tool used to organize information about the elements | The periodic table |
| The basis for the arrangement of atoms on the Periodic Table is: | the number of protons in its nucleus (the atomic number) |
| The information on the periodic table can be used to predict: | chemical reactivity |
| The boxes for all of the elements are arranged in increasing order of: | atomic number |
| The elements have increasing _________ character as you read from left to right across the table | Nonmetallic |
| These are along the stair-step line. | Metalloids |
| The metalloids have properties of both: | metals and nonmetals |
| These are located to the right of the stair step line. | non-metals |
| These tend to lose electrons in chemical reactions. | Metals |
| In chemical reactions, metals tend to these. | positive ions |
| These tend to gain electrons in chemical reactions, forming negative ions. | non-metals |
| Gaining or losing electrons makes an atom this. | an ion |
| Gaining or losing neutrons makes an atom this. | an isotope |
| Gaining or losing a proton makes an atom into this. | a completely different element |
| The number of outer energy level electrons. | Valence |
| This determines an element's chemical properties or chemical reactivity. | The number of electrons in the outermost energy level. |
| The vertical columns in the table | Groups or families |
| Elements in each group have similar properties because they have this. | The same number of electrons in the outermost energy level. |
| The horizontal rows on the Periodic Table | Periods |
| Atoms react to form chemically stable substances that are held together by these. | Chemical bonds |
| To become chemically stable, atoms: | gain, lose or share electrons |
| When two elements react chemically, these are formed. | Binary compounds |
| When a metallic element reacts with a nonmetallic element, their atoms gain and lose electrons respectively, forming: | Ionic bonds |
| Generally, when two nonmetals react, atoms share electrons, forming: | Covalent bonds |
| Matter can undergo ________ and ________ changes. | physical and chemical |
| In ____ changes, the chemical composition of the substances does not change. | physical |
| In _______ changes, different substances are formed. | chemical |
| This law states that regardless of how substances within a closed system are changed, the total mass remains the same. | The Law of Conservation of Matter |
| Which law states that energy cannot be created or destroyed only changed from one form to another? | The Law of Conservation of Energy |
| Changes that take place in a chemical reaction can be represented by a: | Chemical equation |
| The chemical formulas of the _____ are written on the left. | Reactants |
| In a chemical equation, an arrow indicates: | A change to a new substance |
| Chemical formulas of the ______ are written on the right. | Products |
| Two broad types of chemical reactions are: | Exothermic and endothermic |
| A chemical reaction in which energy is released is: | exothermic |
| A chemical reaction in which energy is absorbed is: | endothermic |
