CH1: Atomic and Molecular Structure

The Periodic Table Semimetals Non metals Metals A L K I C A R B O N O G A S A L K I N I T R O G E Semimetals H A L O G E N S A L K I N E R T H C A R B O N O X Y G E N B O R N TRANSITION INNER TRANSITION

Periods: 1-7 Groups/Families -similar properties -same # of valence e-

Periodic Table

s p d f Orbitals: s, p, d, f Trends Increase in electronegativity, ionization energy, nonmetallicity Increase in atomic/ionic radius, metallicity s p d Ionization energy: Energy needed to take away an e- Electronegativity: attraction to e- f Trends Elements are arranged according to atomic #, atomic mass and properties (trends).

Trends

What group of elements can represent W? What group of elements can represent X?

Atoms The nucleus contains most of the mass Electrons contain most the volume Most of the atom is empty space e- + o

Structure of Atom

e- vary 3 4 5 6 7 8 1 2 Valence electrons -These electrons are responsible for bonding Valence electrons -Atoms want 8 electrons -Atoms will lose/gain electrons to get 8  ions -Atoms lose e- and become +  cations -Atoms gain e- and become -  anions e- vary 3 4 5 6 7 8 1 2 Various + charges +1 +2 +3 -3 -2 -1

Valence electrons & trends

Atomic # (the smaller of the two numbers) Atomic # = proton # (and electrons when neutral) S 16 32.06959 Atomic mass = protons + neutrons Symbol: Stands for the element Charge = protons - electrons Atomic Mass

Noble Gas Configuration Shortens the electron configuration Magnesium-12: 1s22s22p63s2 This is the configuration for the noble gas Ne Can rewrite the configuration using Ne in place of its configuration Magnesium-12: [Ne]3s2

CH2: Chemical Bonds

Types of Bonds Covalent Bonds (nonmetals) Electrons are shared CH4 Ionic Bonds (metal + nonmetal) Gain/lose electrons NaCl Metallic Bond (only metals) Valence electrons flow through the atoms Sea of electrons Au

Monatomic vs Diatomic Elements Monatomic elements These elements exist on their own as atoms All the noble gases are monatomic Diatomic elements These elements exist in pairs H2 F2 O2 N2 Cl2 Br2 I2 Mr. H FONCl BrI

H. FONCl BrI

Lewis Dot Structures Use the valence electrons to draw dots around elements and compounds. Count valence e- total, fulfill octets of the outer elements, fulfill octet of central atom If too many e-, put extra electrons on central atom If not enough e-, use double/triple bonds Groups have the same Lewis Dot Structures Ex: F N S

Al C O CO2 Cl2 O2 N2