Just the basics
Structure of an Atom
Atoms are the smallest particles that retain the properties of an element. Protons are found in the nucleus of an atom and are positively charged. Neutrons are also found in the nucleus and are neutrally charged, and electrons are found in the electron cloud with a negative charge. Electron orbitals hold the electrons within the electron cloud. The orbitals are most stable when the outermost orbital is full. The first orbital from the center of an atom contains two electrons, and then the following two orbitals contain eight electrons.
On the periodic table, each element is represented by its atomic symbol, atomic number, and atomic mass. The atomic number of an element is the amount of protons the element contains. The atomic mass is the amount of protons in an element added to the amount of neutrons. The amount of neutrons in an element is equal to the difference of the atomic mass and amount of protons
Isotopes, Ions, and Ionic Bonds
Isotopes are atoms of a single element that contain different numbers of neutrons. An ion is an atom or molecule with a net electric charge due to the loss or gain of one or more electrons. Ionic bonds are bonds between oppositely charged ions that form between metals and non-metals. Atoms gain or lose an electron to form a bond. When atoms gain an electron they obtain a negative charge, and when the atom loses an electron it obtains a positive charge.
Compounds and Molecules
Compounds are two or more elements that are bonded together. Molecules are the smallest part of the compound that still retains its properties.
The pH Range is used to measure the amount of acidity or basicity of a solution. When water ionizes it releases equal amounts of hydrogen and hydroxide ions. Acids release hydrogen ions into a solution, represented by H+. Bases release hydroxide ions into a solution, represented by OH-. Buffers resist a pH change by accepting hydrogen ions or hydroxide ions, thus maintaining homeostasis.
In a covalent bond, atoms fill their outer shell by sharing electrons. Covalent bonds form between non metals and form when the outer shells of the atoms overlap. Double and triple covalent bonds form when atoms share more than one pair of electrons. A single covalent bond is represented by: H-H A double covalent bond is represented by: O=O
A triple covalent bond is represented by: N ≡N
Biology Midterm Review Basic Chem