Question | Answer |
Atom | the smallest piece of an element |
Proton | particle in the nucleus of an atom with a positive charge |
Neutron | particle in the nucleus of an atom that does not have a charge |
Electron | particle found outside of the nucleus (shell/cloud) and has a negative charge |
Atomic Number | the number of protons in an atom (also electrons) |
Isotopes | atoms of the same element such as hydrogen but with different numbers of neutrons |
Mass Number | the number of both protons and neutrons in an atom |
Periodic Table | a way of organizing all of the elements found in the universe |
Periods | horizontal rows on the Periodic Table (The period number is the number of shells) |
Groups/Families | vertical columns on the Periodic Table where elements have similar chemical properties. |
Valence Electrons | the number of outer electrons in an atom. (It is the Group Number for the Main Elements) 1/2/3b...8b |
Metals | elements on the LEFT side of the Periodic Table that are usually soft/shiny/malleable/ductile/low specific heat/high melting points/good conductors |
Non-metals | elements on the RIGHT side of the Periodic table that are usually dull |
Transition Metals | elements in the middle of the Periodic Table |
Metalloids | elements along the zig zag stair case that have properties of both metals and nonmetals |
Element | a substance made up of only one atom |
Compound | a substance made up of two or more elements that have been chemically combined |
Mixture | two or more substances brought together but are not combined chemically and still keep their same properties |
Matter | anything that has mass and takes up space |
States of Matter | solid/liquid/gas/plasma |
Solid | has a definite shape and definite volume |
Liquid | has a definite volume but not a definite shape |
Gas | has a definite volume but not a definite shape |
Plasma | a gas at high temperatures where it has become electrically charged (lightning/fluorescent lights/Auroras/stars) |
Physical Changes | a change where the material keeps it's same properties such as tearing |
Evaporation | physical change where a liquid becomes a gas (usually due to increasing temperature) |
Condensation | physical change where a gas becomes a liquid (usually due to cooler temperatures) |
Chemical Changes | change where a substance is changed into a new substance with new properties after a chemical reaction |
Physical Properties | properties that describe the appearance of a substance such as color/shape/texture/luster/melting point/mass/density/etc. |
Texture | the surface features of a substance (smooth/rough) Physical Property |
Luster | describes how a substance reflects light (shiny/metallic/dull) |
Physical Property | describes the appearance of a material |
Ductile | physical property of metals being pulled or stretched into wire without breaking |
Malleable | physical property of metals being hammered into sheets or bent into different shapes without breaking |
Mass | the amount of matter in an object (measured with a balance) (unit is gram) Does not change |
Volume | the amount of space an object takes up (measured with graduated cylinder or ruler) (units are ml or cm3) |
Density | the measure of how squeezed together particles are in an object ( units are g/ml or g/cm3) |
Melting Point | the temperature at which a solid changes to a liquid |
Boiling Point | the temperature at which a liquid changes to a gas |
Chemical Properties | properties that describe how a substance will react chemically with another substance |
Flammability | the ease atwhich a material will burn |
Corrosive | the ability of a substance to destroy another substance through a chemical reaction (acids corrode metals) |
Reactivity | the degree that a substance will react chemically |
Toxicity | the degree that a substance can damage an organism |
Subscript | the number written below an element that indicates the number of atoms present (example H2O) |
Coefficient | the number written in front of a formula that indicates the number of molecules that are present (example 3HCl) |
Law of Conservation of Mass | the mass of the reactants will be the same as the mass of the products. Matter is not created or destroyed. |
Reactants | the substances on the left side of an equation involved in the reaction |
Products | the substances on the right hand side of an equation that are formed in a reaction |
Exothermic | a reaction where heat is released ( the beaker gets hot) |
Endothermic | a reaction where heat is absorbed (the beaker gets cold) |
Chemical Bond | the force of attraction that holds atoms together in compounds or molecules |
Signs of a Chemical Reaction | color change/new odor/bubbling/temperature change/solid precipitate |
Hypothesis | a testable explanation or prediction |
Conclusion | summarizing the data and results of an experiment and either accepting or rejecting the hypothesis |
Independent Variable | the variable that we change to see the effect it will have on the dependent variable (example: amount of water ) |
Dependent Variable | the variable that we are studying to see how it is affected by a change in some other variable (example:height of plants) |
Controlled Variables | variables that are kept constant so that the changes that we observe are only due to the independent variable that we change |
Data | the observations made in an experiment |
Model | a simple or abstract way of representing something. Example: used to describe atoms |
Topographic Map | a map that shows the surface features or elevation of an area |
Mass | the measure of the amount of matter in an object. (Instrument-balance) (Unit is grams) ( NEVER CHANGES) |
Volume | the measure of the amount of space an object takes up. (Instrument-graduated cylinder or ruler) (unit is ml or cm3) |
Density | the amount of matter squeezed into a certain space. (unit- g/ml or g/cm3). Physical Property |
Buoyancy | The upward force exerted on an object that is placed in a fluid |
Archimedes Principle | The buoyancy force is equal to the weight of water that is displaced by the object |
Pure Substance | An element or compound. |
Mixture | Two or more substances that are brought together but do not combine chemically. |
Homogeneous mixture | A mixture that has the same composition throughout ( example: salt water) |
Heterogeneous mixture | A mixture that does not have the same composition throughout. ( example: salad, pizza) |
sublimation | A change in state from a solid straight to a gas ( example- dry ice ) |
polar | the uneven arrangement of electrons in a molecule ( one end is slightly positive, one negative) |
adhesion | The tendency of a material to stick to another material ( water-glass ) |
cohesion | The tendency of molecules to be slightly attracted to each other (water beading up) |
Ionic bond | A bond that results from the gaining or losing of electrons ( metals-nonmetals) |
Covalent bond | A bond that results from the sharing of electrons (nonmetals - nonmetals |
Solubility | A property that describes how much solute can be dissolved at a given temperature |