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IONIC AND COVALENT STRUCTURES. IONIC = metal + non metal COVALENT = non metal + non metal. Notebook Layout. Ionic Background. Octet Rule Atoms try to fulfill their Octet by either GAINING or LOSING electrons from their VALENCE shell Groups 1 – 4 LOSE Groups 5 – 7 GAIN.
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IONIC AND COVALENT STRUCTURES IONIC = metal + non metal COVALENT = non metal + non metal
Ionic Background • Octet Rule • Atoms try to fulfill their Octet by either GAINING or LOSING electrons from their VALENCE shell • Groups 1 – 4 • LOSE • Groups 5 – 7 • GAIN
Ionic Background • Charges • Dependent on Valence Electrons • Octet Rule • + = electrons LOST • - = electrons GAINED • F = ? • Na = ? • N = ? • Li = ?
IONIC FLOW BALANCE DOTS FINAL PRODUCT DONATE & RECEIVE
BALANCE • Balance the elements in your compound • Determine your charges • Balance them (equal amounts of + and - ) • The compound must show a Neutral formula! • Mg & Cl • Mg 2+Cl1- • Mg 2+Cl1- • Bring the number down NOT the charge • MgCl2 • Our balanced formula has ONE magnesium and TWO chlorines
DOTS • Draw ALL the dot structures for your Balanced compound • REMEMBER • Dot structures only represent the VALENCE electrons • Look at the element’s GROUP number for its VALENCE number • MgCl2 • We have one magnesium and two chlorines • So we need…
DONATE AND RECEIVE • CATIONS • Are the metal elements that DONATE their electrons (+) • ANIONS • Are the non metal elements that RECEIVE their electrons (-) • Label cation/anions and show where the electrons are going
FINAL PRODUCT • The final product shows the elements AFTER the electrons have been DONATED & RECEIVED • Charges are shown • Elements in Brackets
Covalent Background • LEWIS DOT STRUCTURES • BONDS (shared electrons) • Shown by lines between elements • 1 bonds = 2 shared e- • 2 bonds = 4 shared e- • 3 bonds = 6 shared e- • LONE PAIRS • Pairs of non bonding electrons
NASL NUMBER of full valence electrons AVAILABLE valence electrons LONE pairs SHARED electrons
Number of FULL valence electrons • If all the valence shells involved were full… • For example… • NH3 • Nitrogen full octet = 8 • Hydrogen full octet = 2 • Hydrogen full octet = 2 • Hydrogen full octet = 2 • 14 electrons
Available valence electrons • How many valence electrons are actually available on the elements??? • NH3 • Nitrogen = 5 • Hydrogen = 1 • Hydrogen = 1 • Hydrogen = 1 • 8 electrons
SHARED electrons (bonds) • Every 2 electrons is ONE bond • SHARED = N – A • NH3 • N – A • 14 – 8 • 6 SHARED e- • 3 bonds
LONE pairs • Every 2 electrons that are NOT involved in bonding • LONE pairs = A – S • NH3 • A – S • 8 – 6 • 2 LONE pair electrons
NH3 Lewis Dot Structures SHARED -> 3 bonds LONE PAIRS -> 2 electrons
FULL OCTETS?? Nitrogen -> 3 bonds -> 1 lone pair Hydrogen (3) -> 1 bond 1 bond = 2 electrons 1 lone pair = 2 electrons SHARED/BONDED electrons fulfill the Octet