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 |