Chemistry Review Already Graded A

Chemistry Review Already Graded A The Building Blocks of Life Organisms are composed of matter, which is anything that takes up space and has mass. Matter is made up of elements, which are substances that cannot be broken down into simpler substances by chemical reactions. Elements and Compounds Elements are the simplest forms of matter, consisting of unique atoms. A compound is a substance formed by combining two or more elements in a fixed ratio, exhibiting characteristics that differ from those of its individual elements. The three most abundant elements in living matter are carbon, hydrogen, oxygen, and nitrogen. Atomic Structure Atoms are the smallest units of matter that retain the properties of an element. They consist of subatomic particles: neutrons, protons, and electrons. Neutrons have no electrical charge, protons have a positive charge, and electrons have a negative charge. Isotopes and Atomic Properties All atoms of an element have the same number of protons but may differ in the number of neutrons, resulting in isotopes. The atomic number is the number of protons in an atom's nucleus, while the mass number is the sum of protons and neutrons. The atomic mass is the total mass of an atom, often approximated by the mass number. Energy and Electron Shells Energy is the capacity to cause change, while potential energy refers to the energy stored due to an object's location or structure. In atoms, electrons occupy specific energy levels or electron shells, which determine their chemical behavior. Valence electrons are those in the outermost shell and play a crucial role in chemical bonding. Chemical Bonding Covalent bonds form when two atoms share one or more pairs of valence electrons. Molecules are groups of atoms held together by covalent bonds. Structural formulas use notation to represent atoms and bonding patterns. What is a compound ️A combination of two or more different elements What is electronegativity ️An atoms attraction for the electrons in a covalent bonds. The more electronegative an atom, the more strongly it pulls shared electrons toward it What is a nonpolar covalent bond ️The atoms share the electron equally What is a polar covalent bond ️One Atom is more electronegative and the atom do not share the electrons equally What are ionic bonds ️In attraction between an anion and a cation. Atoms sometimes strip electrons from their bonding partners What is an ion ️A charge atom or molecule What is a cation ️A positively charged ion What is an anion ️A negatively charged ion Is a covalent bond a strong bond ️Yes What are weak chemical bonds ️Hydrogen bonds and ionic bonds, hydrophobic and hydrophilic interactions, van der waals forces What are hydrogen bonds ️A hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom What are van der waals interactions? ️Attractions between molecules that are close together as a result of these charges... If electrons are distributed asymmetrically in molecules or