1. Define a Family.
2. What is a period?
3. What is the symbol for the following elements?
a. Magnesium
b. Potassium
c. Iron
d. Copper
e. Aluminum
4. What are the names of the following elements?
a. C
b. Cl
c. Au
d. Sr
5. What period are the following element in?
a. He
b. Ge
c. Rb
d. I
6. What group are the following elements?
a. Sulfur
b. Ca
c. Iodine
d. Fe
7. Give me an atom with the following characteristics.
a. Halogen
b. Alkali metal
c. Nobel gas
d. Transition metal
e. Nonmetal

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.

Express the following number in scientific notation. 0.026890 =

)benzene and toluene form nearly ideal solutions. consider an equimolar solution of benzene and toluene. at 20 °c the vapour pressures of pure benzene and toluene are 9.9 kpa and 2.9 kpa, respectively. the solution is boiled by reducing the external pressure below the vapour pressure. calculate (i) the pressure when boiling begins, (ii) the composition of each component in the vapour, and (iii) the vapour pressure when only a few drops of liquid remain. assume that the rate of vaporization is low enough for the temperature to remain constant at 20 °c.