General Chemistry 3rd Quarter Reviewer PDF

ionization energies. When this GENERAL CHEMISTRY​ is the case, we refer to them as the “first ionization energy" 3rd Quarter Reviewer or "IE1”, “second ionization...

ionization energies. When this GENERAL CHEMISTRY​ is the case, we refer to them as the “first ionization energy" 3rd Quarter Reviewer or "IE1”, “second ionization energy" or "IE2", and so on. Goodluck po! ​ Ion – is a charged atom or molecule. It is charged because the number of electrons does not equal the LESSON 1 - IONIC AND COVALENT number of protons in the BONDS atom or molecule. ​ How are the Ionic compounds formed? ○​ Two neutral atoms close to each other can PERIODIC TRENDS undergo an ionization process in order to obtain a full valence shell ○​ Due to ionization, electrons are transferred from one atom to the other. ○​ The atom giving up the electron becomes positively charged ( cation) and the atom receiving the electron becomes negatively IONIC BOND charged (anion) ○​ The ions are bonded ​ Ionic Bond – bond in which one or more electrons from due to coulombic forces one atom are removed and of attraction (unlike attached to another atom, charges attract!) resulting in positive and ○​ Generally, metallic negative ions which attract atoms donate electrons each other. to non- metallic atoms. ​ Ionization energy (IE) – is Examples of ionic the amount of energy it takes to detach one electron from a compounds: NaCl, KCl, neutral atom. Some elements MgBr2 and etc. actually have several 1  Examples of how Lewis structure of Ionic compounds are drawn: ​ OCTET RULE ​ According to Lewis, atoms combine in order to achieve a more stable electron configuration. And this maximum stability is attained when an atom is isoelectronic (same # of electrons) with a noble gas. Except for He, the noble gases COVALENT BOND have eight outer electrons or FORMATION OF THE an octet of electrons. The COVALENT BOND Octet Rule states that when ​ Gilbert Lewis suggested that atoms of elements combine to the chemical bond is formed form compounds, they tend to by sharing of electrons in lose, gain, or share electrons atoms. to achieve the same electron For hydrogen molecule, this arrangement as the noble gas is depicted by nearest them in the periodic table. ​ LEWIS DOT STRUCTURE In combining with other atoms, only outer electrons, the valence electrons, are involved. To keep ​ The two electrons are shared track of these valence electrons, the equally between the two Lewis dot symbol is used. The Lewis atoms forming a covalent Dot Symbol consists of the symbol bond. The bond is typically of an element and one dot for each depicted by a single line, H-H. The electrons are valence electron in an atom of the attracted to the nuclei of both element. atoms keeping the atoms together to form a molecule. 2  double sided arrow shows EXAMPLE: that the structures are F2 molecule resonance structures. A resonance structure is one of two or more Lewis structures for a molecule that cannot be represented accurately by only one Lewis structure. ​ The representation of the LESSON 2: INTERMOLECULAR covalent compound above is FORCES called the Lewis Structure. In ​ INTERMOLECULAR FORCES the Lewis structure, shared - are attractive forces that act electrons that form a bond is between molecules or particles represented by a line or a pair in the solid or liquid states. of dots; lone pairs are These attractive forces are represented by dots above the much weaker than bonding atom. forces. I.​ LEWIS STRUCTURE AND 3 TYPES Of INTERMOLECULAR RESONANCE FORCES 1.​ Write the Lewis ​ LONDON DISPERSION structure for the FORCES - result from ozone molecule, temporary dipole moments O3. included in ordinary nonpolar a.​ The skeletal molecules. As electrons move structure is around the nucleus, an uneven distribution causes momentary charge b.​ Valence electrons: separations. Slightly positive 3(6) = 18 sides of a molecule are c.​ Lewis structure is: attracted to the slightly negative sides of the adjacent molecule. We represent the ozone molecule using the two structures presented as follows: ​ Each of the above structures is called a resonance structure. The 3  DEFINITION OF TERMS: ▪​ PHASE is a homogeneous part of a system in contact with other part of the system, but separated by well-defined boundaries. ▪​ CONDENSED PHASES are solids and liquids. ▪​ INTRAMOLECULAR FORCES hold ​ Dipole-dipole forces – are atoms together in a molecule. attractive forces between polar ▪​ INTERMOLECULAR FORCES are molecules (molecules that attractive forces between molecules. possess dipole moments). In polar molecules, the electrons are unevenly distributed DIFFERENT PROPERTIES OF because some elements are LIQUID more electronegative than 1.​ Surface Tension others. The partial negative side of one molecule is attracted to the partial positive side of another molecule. o​ Molecules within a liquid are ​ Ion-dipole forces – polar pulled in all directions by molecules are attracted to intermolecular forces. Molecules ions. The positive pole is at the surface are pulled attracted to a negative ion downward and sideways by (anion), while the negative other molecules, not upward pole is attracted to a positive away from the surface. ion (cation). o​ These intermolecular forces tend to pull the molecules into the liquid and cause the surface to tighten like an elastic film or “skin”. 2.​ Capillary Action 4  o​ The stronger the intermolecular forces of attraction, the lower the vapor pressure of a liquid. ​ Two types of forces are involved 5.​ Molar heat of in capillary action: Cohesion is vaporization the intermolecular attraction o​ If the intermolecular attraction is between like molecules (liquid strong, it takes a lot of energy to molecules). Adhesion is an free the molecules from the attraction between unlike liquid phase and the heat of molecules (such as those in vaporization will be high. water and in the particles that o​ The boiling point is related to make up the glass tube). molar heat of vaporization: the higher the molar heat of 3.​ Viscosity vaporization, the higher the boiling point. o​ The boiling points of substances often reflect the strength of the intermolecular forces operating among the molecules. At the BP, enough energy must be supplied to overcome the attractive forces among molecules before they o​ Liquids that have strong can enter the vapor phase. intermolecular forces have higher viscosities than those THE UNIQUE PROPERTIES OF that have weak intermolecular WATER forces. ​ Water is a good solvent. o​ Viscosity decreases as temperatu ​ water has a high specific heat. increases. ​ The boiling point of water is unusually high. 4.​ Vapor pressure of a liquid ​ Solid water is less dense, and o​ Vapor pressure is independent in fact floats on liquid water. of the amount of liquid as well as the surface area of the liquid PROPERTIES OF SOLID in contact with the gas. TWO TYPES OF SOLIDS: o​ The equilibrium vapor ​ Crystals pressure is the maximum vapor ○​ arranged in fixed pressure of a liquid at a given geometric patterns or temperature and that it is lattices constant at a constant ​ Amorphous Solids temperature. It increases with ○​ have a random temperature. orientation of particles. They are considered Super-cooled liquids 5  where molecules are ○​ Hard, Very high melting arranged in a random point, Poor electrical manner similar to the conductors liquid state. ○​ Poor heat conductor ○​ Soften gradually when ○​ Brittle they are heated. They tend to melt over a wide PHASE CHANGES range of temperature. these are transformation of matter from one physical state to another. TYPES OF CRYSTALS ​ Ionic Crystals - these crystals Phases of matter: are made of ions. These ions ​ Solid - atoms are compressed form electrostatic interactions and uniform that hold the crystals lattice ​ Liquid - atoms are in contact together. with each other but not ○​ CHARACTERISTICS definite shape. ○​ Hard, High melting ​ Gas - atoms rarely interacts point, Poor electrical with each other conductor(solid), Good FEATURES OF THE PHASE electrical DIAGRAM conductor(liquid), ​ Three areas - indicates the brittle. phase of matter within the ​ Molecular Crystals - are area. crystals made of atoms. The ​ Three Lines - the change of atoms or molecules are held phrase of the substance together by a mix of hydrogen ​ Two important points - bonding/dipole-dipole or ○​ Triple point - a specific Dispersion forces, and theses set of T and P. All are the attractive forces that phases of matter are broken when the crystal co-exists melts. ○​ Critical Point - ○​ CHARACTERISTICS removes the line ○​ Soft, low melting point, between the liquid and Poor electrical gas state. conductors ○​ Poor heat conductor ○​ Brittle ​ COVALENT Netwrok Crystals - are crystals made of atoms in which each atom is covalently bonded to its nearest neighbors. ○​ CHARACTERISTICS 6