Lesson 2.1: Basic Chemistry

Atoms: Atoms are the smallest component of an element The subatomic particles that make up atoms are: Protons Neutrons Electrons

Parts of an Atom: Protons: positively charged (+) Neutrons: no charge Both about equal in mass/weight Together makeup the nucleus, at the center of the atom

Parts of an Atom: Electrons: negatively charged (-) 1/1840 mass of a proton In constant motion surrounding the nucleus Equal # protons & electrons

Parts of an Atom: Valence electrons: the outer most electrons involved with bonding Equal to the group number the element is in

Elements: Element: a pure substance that consists entirely of one type of atom Atomic number: # of protons Mass number: # of protons + neutrons

Isotopes: Isotope: an element with a different number of neutrons DO NOT TAKE HOME, THANKS! Isotopes: Isotope: an element with a different number of neutrons How is an element similar to an isotope? Same # of protons & electrons How is an element different from an isotope? Different # of neutrons

Chemical Bonds: Ionic Bond: formed when one or more electrons are transferred from one atom to another Strongest bonds Atoms that lose an electron become positively charged; gain an electron become negatively charged Charged atoms are called ions

Chemical Bonds: Compound: a substance formed by the chemical combination (ionic bonds) of two or more elements The physical and chemical properties of a compound are usually very different from those of the elements from which it is formed Na (Sodium) + Cl (Chlorine)  NaCl (Salt)

Chemical Bonds: Covalent Bond: formed when one or more electrons are shared between two atoms Molecule: formed when 2 or more atoms are joined by covalent bonds Example: H2O; O2

Non-Chemical Bonds: Mixture: two or more elements or compounds that are physically combined but not chemically combined Suspensions: material that does not dissolve in a mixture Example = salt water

Non-Chemical Bonds: Solution: A homogeneous mixture of 2 or more substances Solute: substance being dissolved (ex. salt) Solvent: dissolver (ex. water) Example = Soda