Summary Chapter 1-2 General, Organic, & Biological Chemistry Janice Gorzynski Smith

CH 1-2 Concepts to be Familiar With  Classification of matter: pure substances & mixtures  Homogeneous vs Heterogeneous  Distinguish the difference between chemical and physical properties & changes  We represent uncertainty with significant figures  You do not need to memorize Sig Fig rules  Scientific Notation  Conversions within the metric system and non metric units  Temperature conversions  Density & Specific gravity  Familiarity with how compounds will be drawn  Molecular formulas  Structure of an atom: protons, neutrons, electrons  Atomic number, isotope mass number, atomic weight  Navigate the periodic table: properties shared within a group, trends, metals/metalloids/nonmetals  Determine valance electrons & draw electron dot representations  Ionization Energy & Atomic Size

Conversions & Equations To Memorize Unit Conversions For metric units (m, kg, s, K, mole): mega (M) 10 6 kilo (k) 10 3 centi (c) milli (m) micro (μ) nano (n) Pico (p) Time conversions: d  hr  m  s 1 mL = 1 cm 3 T(kelvin) = T(°C) Equations Density = mass / Volume d = m/V d H2O = 1 g/mL = 1 g/cm 3 Specific Gravity = density substance / density of water Coefficient: A number between 1 and 10. y x 10 x Exponent: Any positive or negative whole number.

Elements & Molecules X = Element symbol (ie O = oxygen) A = Isotope Mass Number = # protons + # neutrons Z = Atomic Number = # protons 6 C atomic number element symbol atomic weight (amu) = weighted average of atomic weight of isotopes Elements on the Periodic Table Molecular Formula: A x B y Ex: CH 3 O Drawing Molecules: Methane CH 4

Properties of Groups 1A2ABB7A8A Alkali MetalsAlkaline Earth Metals Transition Metals Lanthanide & Actinide HalogensNobel Gases Very reactive Metals except for H +1 ions React with Oxygen to form compounds that dissolve into alkaline solutions in water Reactive +2 ions Oxygen compounds are strongly alkaline Many are not water soluble Metals Form ions with several different charges (oxidation states) Tend to form +2 and +3 ions Lanthanides 58 – 71 Actinides 90 – 103 Actinides are radioactive Reactive Form diatomic molecules in elemental state -1 ions Salts with alkali metals Inert Heavier elements have limited reactivity Do not form ions Monoatomic gases

Properties of Metals, Nonmetals, Metalloids MetalsNonmetalsMetalloids Metallic luster, malleable, ductile, hardness variable Conduct heat and electricity Solids at room temperature with the exception of Hg Chemical reactivity varies greatly: Au, Pt unreactive while Na, K very reactive Brittle, dull Insulators, non- conductors of electricity and heat Chemical reactivity varies Exist mostly as compounds rather then pure elements Many are gases, some are solids at room temp, only Br 2 is a liquid. Properties intermediate between metals and nonmetals Metallic shine but brittle Semiconductors: conduct electricity but not as well as metals: examples are silicon and germanium

Valence Electrons 1 2 X X X X X X X X X X Count the number of elements in the row (period) that lead up to the element (Se). Remember, do NOT count the transition metals, lacthanides, and actinides. Example: Determine the valence electrons of Selenium (Se): 1.Find Se on the periodic table 2.Focus on just the row (period) Se is in 3.Count the number of electrons in the s and p orbitals (ie, count to Se from the left side of the row) Se Electron Dot Symbols: Represent the valence electrons by drawing them around the element symbol for Selenium.

Periodic Trends Ionization Energy INCREASING Size INCREASING