Answer: Order of the elements from most reactive to least reactive is:
Mg > Zn > Fe > H > Cu
Explanation: Reactivity of the elements is the tendency of the elements to loose or gain electrons with ease.
As, all the given elements are metals, so the metals which will loose electrons easily will be more reactive. To study the reactivity of metals, we use reactivity series.
The metals which are more reactive are placed on the top of the reactivity series and which are less reactive are placed at the bottom.
Hence, the order of the elements from most reactive to least reactive is:
Mg > Zn > Fe > H > Cu
Reactivity series is attached below.
Answer:
Metalloids
Explanation:
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The patch area in square kilometers is 1.59*10⁻⁹ km₂
Why?
This is an unit conversion problem. We have to convert from cm² to km². We can do that by knowing that there are 100 cm in 1 m, and 1000 m in 1 km, so 100000 cm=1km. Knowing that we can apply the following conversion factor:

Now to convert this value to scientific notation, we have to move the decimal point to the right until we get a whole number, and the exponent of the number 10 is going to be the number of spaces we moved to the right (negative), so the final answer is:

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From the conversion of units:
1 cm^3 is equivalent to 1 mL
1 L is equivalent to 1000 mL
therefore,
to convert from liter to cm^3, we simply multiply by 1000.
Note that the multiplication will be done in the denominator.
Based on this:
density = (0.625 g/l) x (1g/1000 cm^3) = <span> 0.000625 g/cm^3
= 6.25 x 10^-4 g/cm^3</span>