Formula of a compound is AF3. what is the valency of a

Which of these properties, used alone, would be least useful in identifying most minerals? a. color b. luster c. streak d. density

Ahypothrticalax type of ceramic material is known to have a density of 2.10 g/cm3 and a unit cell of cubic symmetry with a cell edge length of 0.57 nm. the atomic weights of the a and x elements are 28.5and 30.0 g/mol, respectively. on the basis of this information, which of the following crystal structures is (are) possible for this material: sodium chloride, cesium chloride, or zinc blende

Ariver current has a velocity of 5km/h relative to the shore, and a boat moves in the same direction as the current at 5 km/h relative to the river. how can the velocity of the boat relative to the shore be calculated?