Chemistry

Periodic Table  Group – Vertical columns on PT  Period – Horizontal rows on PT

Main-Group Elements  Groups 1, 2, and 13-18

Main-Group Elements  The chemical properties of the main- group elements depends on their number of valence electrons  Valence electrons are the outermost electrons involved in chemical bonding

Valence Electrons & Chemical Properties  Each group of the main-group elements has the same number of valence electrons  Each element wants to be as stable as possible  All main-group elements want a full shell of electrons, which is 8 valence electrons

Valence Electrons & Chemical Properties  Each group forms ions based on the easiest way to obtain this full shell  Also known as the octet rule

Family Groups  Noble Gases (Group 18)  Examples: Ne, Xe  Description: stable, unreactive group of gases  Number of Valence Electrons: 8  Forms NO ions

Family Groups  Halogens (Group 17)  Examples: F, Cl  Description: Highly reactive group of gases  Number of Valence Electrons: 7  Forms 1- ions

Family Groups  Alkali Metals (Group 1)  Examples: Na, K (not H)  Description: Highly reactive group of metals  Number of Valence Electrons: 1  Forms 1+ ions

Brainiac Movie

Family Groups  Alkaline-Earth Metals (Group 2)  Examples: Be, Mg  Description: Slightly less reactive group than alkali metals  Number of Valence Electrons: 2  Forms 2+ ions

Family Groups  Transition Metals (Group 3 – 12)  Examples: Fe, Au, Ag  Description: Fairly stable group of metals  Forms multiple ions

Family Groups  Lanthanides & Actinides  Location: Bottom 2 periods of PT  Description: Heavy metals, synthetics, radioactive

States of Matter  Metals and Nonmetals (Staircase)

SECTION NEEDS TO BE REDONE WITH THE GROUP/PERIOD TRENDS OUTLINED FIRST!!!!!!!!!!!!!!!!!!!!!

Periodic Table Trends  Atomic Size  Definition: The volume occupied by the electrons around a nucleus  Period Trend  Caused by: Increasing Effective Nuclear Charge

Atomic Size  Effective nuclear charge is the amount of charge felt by outer electrons in an atom  Group trend  Caused by: Increasing electron energy levels

Ionization Energy  Definition: The amount of energy required to remove one electron  Period trend  Caused by: Inc. Effective Nuclear Charge

Ionization Energy  Group trend  Caused by: Electron shielding  Electron shielding occurs when inner electrons shield outer electrons from the pull of the nucleus

Electron Affinity  Definition: The attraction of an atom for an electron  Period Trend  Caused by: Inc. Eff. Nuclear Charge

Electron Affinity  Group trend  Caused by: Inc. electron shielding

Electronegativity  Definition: How much an atom in a chemical bond attracts electrons  Period trend  Caused by: Inc. Eff. Nuclear Charge

Electronegativity  Group trend  Caused by: Electron shielding/Inc. electron energy levels

Electron shielding Electron energy levels Effective Nuclear Charge

Filling Electron Orbitals  Orbitals are the area in space where electrons are found  Each individual orbital holds 2 electrons  There are four main shapes which hold a different number of electrons

Shapes of Orbitals  The four shapes are s, p, d, and f

Shapes of the Orbitals  Each shape holds a different number of orbitals  s has 1 orbital, p has 3 orbitals, and d has 5 orbitals 

Energy Levels  Each period is a new energy level  Like an elevator, electrons cannot exist between energy levels!

General Rules  Aufbau Principle – Electrons fill lowest energy level first  Analogy: Lazy Tenant Rule

General Rules  Pauli Exclusion Principle – Electrons must have opposite spin (up/down) when in the same orbital  Analogy: Yin and Yang Rule

General Rules  Hund’s Rule – Electrons in equal energy orbits fill orbitals with parallel spin  Analogy: Empty Bus Seat Rule

Orbital Notation  Specific order for filling electrons – based on periodic table  Examples  Beryllium  Oxygen

Orbital Notation  Examples  O 2-  Titanium

Electron Configuration  Examples  Silicon  Selenium  Manganese

Shorthand Electron Config  Shorter version of writing electron configurations  Noble Gas Core – inner core of electrons not involved in chemical bonding

Shorthand Electron Config