Power= current*voltage or P=IV
so 16 watts=I*7 volts
divide on both sides to isolate I so you get
I= 16/7 which is about 2.3 amps
It is stored in the bonds between atoms
Mass of 1 staple = 6.8 g/210 staples
mass of 1 staple = 0.032380952 g
Hope that helps!!
You can look at groups in the same group (the columns), since they tend to have similar properties. For example, the alkali metals in group one react aggressively with water and form white compounds.