How do you determine the number of electrons an atom will gain or loose

In general, metals will lose electrons to become a positive cation and nonmetals will gain electrons to become a negative anion. Hydrogen is an exception, as it will usually lose its electron. Metalloids and some metals can be can lose or gain electrons. This is not always true, as elements such as nitrogen can lose electrons to become positive. When an ionic compound forms, the more electronegative element will gain electrons and the less electronegative element will lose electrons. Hope this helps :)

pure substance: iron,copper

impure substance: water,charcoal

a pan containing water is placed in a positio n where it is exposed to a 10 mile per hour wind. the pan contains a uniform depth of 1.27 cm of water, is quite wide, and has a length of 2.44 m in the wind direction. the water in the pan is at a constant temperature of 15.5 °c.