Name: Date: Period: Notes 2.1: The Nature of Matter Atoms o Atoms are made of three subatomic particles _____________________________ _____________________________ _____________________________ o The ______________ is the basic unit of matter. o The concept of the atom came first from the ___________________ philosopher _________________ nearly _________________ years ago. Protons and Neutrons _________________________ and ______________________ have about the same mass. Protons are _______________ charged particles and neutrons ________________________________. Strong forces bind ____________________ and ____________________ together to form the _______________ of an ___________________. Electrons ___________________ is a negatively charged particle. Only a ________________ the mass of a _______________. In constant motion surrounding the __________________________. They are ____________________ to the _______________ but remain ____________________. Protons, Neutrons, and Electrons Because ______________ have an ____________ number of ______________ and ______________, their positive and negative charges _________________________. Elements and Isotopes A __________________ __________________ is a pure substance that consists entirely of one type of ________________. More than _______________________ are known, but only about _____________________ are found in living organisms. Elements are represented by ___________________________________________________. The number of _____________ in the nucleus of an element is called its _________________________. _________________ of the same element that have different numbers of _________________ are known as ______________________. The total number of ___________ and _____________ in the nucleus of an atom is called its ________________________________. ___________________ are identified by their _______________________________. The ______________________ average of the masses of an element’s isotopes, is called its _____________________________________. Because they have the ______________________________________, all isotopes of an element have the same _________________________________________________. Isotopes Radioactive Isotopes Some isotopes are _______________________, meaning that their ______________ are ________________ and break down at a constant rate over time. _________________________ have a number of important scientific and practical uses. Chemical Compounds A __________________________ is a substance that is formed by the ______________________ or ___________________________ elements in definite proportions. Scientists show the composition of compounds by shorthand known as a ________________________. The _____________________ and ___________________ ___________________ of a compound are usually very _____________________ from those of the elements from which it is formed. Chemical Bonds The atoms in ______________________ are held together by various types of ____________________. __________________________________ involves the electrons that surround each ______________________________________. The electrons that are available to form bonds are called ______________________________________. Ionic Bonds An ___________________________ is formed when one or more electrons are transferred from one atom to another. An atom that loses electrons becomes _____________________. An atom that gains electrons becomes _____________________. These positively and negatively charged atoms are known as ________________. Covalent Bonds Sometimes electrons are _______________________ instead of ____________________. The moving electrons travel about the _______________ of both atoms, forming a ______________________________. When the atoms share ___________ electrons the bond is called a __________________________. Sharing of _________ electrons is a __________________________________________________, Sharing of _________ electrons is a __________________________________________________. The structure that results when atoms are joined together by covalent bonds is a _________________, the smallest unit of most compounds. Van der Waals Forces Because of their ___________, atoms of different elements do not all have the same ability to ____________ electrons. Some atoms have a _______________________________ for electrons than do other atoms. When the atoms in a covalent bond share _____________________, the sharing is not always _______________. Even when the sharing is ____________________, the rapid movement of _____________ can create regions on a molecule that have a ______________________________________________________. When molecules are close together, a ______________________ can develop between the _________________ charged regions of nearby molecules. These ______________________________ forces of attraction are called ________________________________, after the scientist who discovered them. Although Van der Waals forces are _______ as ___________ as _______________________________, they can hold molecules together, especially when the molecules are large. Chapter 2.2: Properties of Water The Water Molecule ___________________________ is a ______________________ molecule. ___________________________ can form multiple _______________________ bonds. Water is one of the few compounds found in a __________________ ______________________ over most of Earth’s surface. ______________________ 10 _______________________ balance out _________ electrons. Polarity Due to the angles of chemical bonds - _____________________ atoms on one end of the __________________ and __________________ atoms on the other end. ___________________ - slight _____________________ charge. __________________ - slight ______________________ charge. Molecule in which the charges are said to be ______________________ _________________________ is said to be __________________________. Charges on a polar molecule are written in ____________________ to show they are __________________. Hydrogen Bonding The _________________________ between a hydrogen atom on one _____________________ molecule and the _______________________ atom on another is known as _____________________ ______________________. ______________________ can form multiple hydrogen bonds - _______________________ _____________________. Not as strong as _________________________ or _______________________ bonds. Cohesion o Cohesion is the attraction between molecules of the _________________ substance. o Causes ____________________ molecules to be _______________ o Produces ___________________ __________________________. ___________________. Adhesion o ________________________ is the attraction between molecules of ________________ substances. o ___________________ ______________________ is the result of water rising in a narrow tube against the force of gravity. Ex. Plants. Heat Capacity Because of the _____________________ hydrogen bonds between ___________________ _________________ it takes a large amount of ________________ _______________ to ________________ the _____________________ of water. Water ______________________ ______________________ is ______________________. Solutions and Suspensions Waters ______________________ gives is the ability to ________________ both _________________ ______________________ and other _____________________ __________________. Water is not always __________________ - found as part of a _________________________. A _______________________ is a material composed of _____________ or ___________ elements or compounds that are _______________ ____________________ ______________________ but not ______________________ ________________________. Two types of mixtures: o _____________________ o _____________________ Solutions If a crystal of table salt is placed in water, sodium and chloride ions on the surface of the crystal are attracted to the polar water molecules. __________________ break away from the crystal and are surrounded by water molecules. The ions gradually become dispersed in the water, forming a type of mixture called a ______________. Suspensions o Some materials do not ________________ when placed in ___________________, but separate into pieces so ______________ that they do not settle out. These are known as __________________________. Acids, Bases and pH _______________ ___________________ sometimes split apart to form ____________ _______________ and __________________ ___________________. Because the number of ______________ ___________ produced is equal to the number of ______________ _________________, _______________ water is __________________. The pH scale The ______ _______________ was developed to indicate the concentration of ________ ions in solution. The ____________________ ranges from _________________________. At a pH of __________ the concentration of _________________________________________ _________________________________________________. Solutions with a pH below 7 are ____________ - more ________ than ____________ ions. Solutions with a pH above 7 are ____________ - more ________ than ____________ ions. Acids and Bases o An ____________ is any compound that forms _______ __________ in solution. o A ____________ is any compound that produces __________ ____________ in solution. Buffers The pH of fluids within most cells in the human body must generally be kept between _________ and _________ in order to maintain homeostasis. If the pH is lover or higher, it will affect the ______________ _____________ that take place _____________________________________. One of the ways that organisms control pH is through dissolved compounds called _______________, which are _____________ ______________ or _________________ that can react with strong acids or bases to __________________________________________________________.