Chem 111 1. Molecules & Their Structures Draw electron dot structures of the following ionic compounds formed from: a) magnesium and oxygen Mg +2 O -2 + N 2. 3. +2 C + S -2 e) calcium and nitrogen -3 3 c) calcium and carbon 2 Ca Na 2 b) lithium and nitrogen 3 Li d) sodium and sulfur Ca +2 2 N -3 d) strontium and fluorine -4 Sr +2 2 F - What simple ion forms most commonly for the following elements? a) Na +1 e) S -2 b) I -1 f) Mg +2 c) K +1 g) Al +3 d) Ca +2 h) N -3 Draw a Lewis structure for each of the following covalent molecules: a) PH3 e) C2F6 F F H P H F C C F H F F remember: a dash between 2 atoms = a pair of electrons in a bond b) SiCl4 f) H2Se Cl Cl Si Cl H Se H Cl c) CS2 g) BCl3 S C S Cl B Cl Cl d) OCl2 Cl O h) NCl3 Cl Cl N Cl Cl 4. Draw Lewis structures of the following compounds that do not obey the octet rule: a) BrF3 d) IF5 FF F F I Br F F F F for clarity, lone pairs are only shown on the central atoms b) XeF4 e) XeF2 F F F F Xe F Xe F c) SeF4 f) SCl6 F Se F F F 5. F F F S F F F Polyatomic ions consist of covalently-bonded atoms that, as a group, bear a charge. Draw Lewis structures of the following polyatomic ions: a) SO4-2 - e) PO4-3 O O S OO - b) SO3-2 - O O P OO- f) ClO3- O O S O- c) NO3- g) NO2- - d) CO3-2 - O O O N+ O C O - - O O N O h) BrO2- - O Cl OO O Br O