chemistry lab work

Identification of Metallic Ions

Questions (Please cite resources

A. All chemical used in this test are binary compounds. What portion of the periodic table is responsible for the color observed?

B. In cooking over an open flame, a yellow flame is often observed when some food is spilled into the flame? What is most likely responsible for the yellow flame color?

C. What problems might be associated with using flame color for identification purposes?

D. Explain how the observed colors are produced

OBSERVATIONS

Part A: PRACTICE EXAMPLES
Count Valence e-	Formula	Electron Geometry	Molecular Geometry
1 N = 5 3 H = 3 8 / 2 = 4 pair	NH3	Tetrahedral	Trigonal pyramidal
	H2O
	CBr4
	SO3 This is not a polyatomic ion … No charge!!!
	PI3
	CH3Cl Carbon is the central atom
	NO 1- 3
	CO 2- 3
	NH +1 4
	CH4
	SO2

For the following compounds, there is more than 1 central atom. Count the total number of valence electrons, divide by 2. Draw the Lewis Structures: share the electron pairs around each atom to complete the bonding. Recall that double and triple bonds may be necessary. Determine the structure on each of the central atoms.

Part B: PRACTICE EXAMPLES
Count Valence E	Formula	Structure	Molecular Geometry
1 C = 4 3 H = 3 1 O = 6 1 H = 1 14 e/2 =7 pair	CH3OH	electron geometry C – tetrahedral O – tetrahedral	C = tetrahedral O = bent 2 bonded 2 non bonded
	CH3NH2
	CH2CH2 Looks like H2C - CH2 Hint ; double bond
	CH3OCH3 Looks like H3C – O – CH3