Reactions between metals and non-metals can be very vigorous.
Example: Sodium (Na) + Chlorine (Cl) → Sodium Chloride (NaCl)
Produces a lot of heat, is explosive at high temperatures.
Products form a three-dimensional lattice structure.
Metal atoms lose electrons, forming positively charged ions (cations).
Non-metal atoms gain electrons, forming negatively charged ions (anions).
Metals have low electronegativities; non-metals have higher electronegativities allowing them to attract electrons.
Octet Rule: Atoms tend to gain or lose electrons to achieve a stable electron configuration similar to noble gases.
Example: Na loses 1 electron, Cl gains 1 electron, resulting in Na+ (2,8) and Cl- (2,8,8).
Illustrate the transfer of electrons during ionic bond formation.
Sodium and Chlorine:
Na (2,8,1) → Na+ (2,8)
Cl (2,8,7) + 1 electron → Cl- (2,8,8)
Group 17 non-metals like Cl form anions with a charge of 1-.
Oxygen (O) (2,6) gains 2 electrons from two lithium (Li) atoms, forming O2-.
Li (2,1) → Li+ (2)
1 Li loses 1 electron; 2 Li required for 1 O.
Magnesium (Mg) (2,8,2) with Oxygen (O) to form Mg2+ and O2-.
Electron transfer: 2 electrons from Mg to O, resulting in a stable lattice.
Reaction Example: Lithium and Nitrogen
Li (2,1) → Li+ (2)
N (2,5) → N3- (2,8)
Balanced equation: 3Li + N → 3Li+ + N3-
Formulas must balance positive and negative charges.
Na+ (1+) + Cl- (1-) → NaCl (1:1 ratio)
Mg2+ (2+) + 2 Cl- (1-) → MgCl₂ (1:2 ratio)
Positive ion symbol written first.
Use subscripts for quantity, omit '1'.
Charges not included in formulas.
Polyatomic ions consist of multiple atoms acting as a single unit with a specific charge.
Example: Carbonate (CO₃²-), Nitrate (NO₃-).
If more than one polyatomic ion is needed, use brackets.
Example: Mg(NO₃)₂
Some can have variable charges. Indicate with Roman numerals.
Example: Iron(II) chloride = FeCl₂, Iron(III) chloride = FeCl₃.
Cations name as the metal (e.g., Sodium Ion).
Anions named based on element name (e.g., Chlorine → Chloride).
Polyatomic anions contain oxygen; names end in -ite or -ate (e.g., Nitrate, Nitrite).