<span>A, b, y c son cambios físicos. D es un cambio químico.</span>
Actinium is the most reactive element or metal in group 3.
Explanation:
Reactivity of an element or metal is defined as its tendency to loose or gain atoms. Group 3 elements consist of metal. We know that reactivity of metal increases as we go down to the bottom of the column.
group 3 metals have 3 electrons in valence shell. They react by loosing 3 electrons. it has oxidation state of +3 and are electropositive.
Group 3 consists of scandium, yttrium, lanthanum and actinium.
Actinium is called actinide.
Answer:
This involves metric conversion and one can easily use dimensional analysis, assuming you know the conversion factors.
1 ng = 10-9 g, or put another way 109 ng = 1 g
1 kg = 103 g
5.27x10-13 kg x 1 g/1x10-3 kg x 1x109 ng/g = 5.27x10-1 ng = 0.527 ng
Looking at the individual steps and following the units, we have...
5.27x10-13 kg x 1 g/1x10-3 g = 5.27x10-10 g (kg cancel leaving g)
5.27x10-10 g x 1x109 ng/g = 5.27x10-1 ng = 0.527 ng (g cancel leaving ng)
