Answer:
Early-warning systems are essential in the case of hurricanes, severe thunderstorms, tornadoes, tsunamis, and volcanoes. All of these can wreak havoc! Let’s take a look at how meteorologists forecast these events and how early-warning systems can help us protect ourselves if we are in their paths.
Explanation:
An atom hopefully this helps
Its d its the only one that makes sense
Answer:
4.52 x 10²⁴ atoms Cl
Explanation:
A mole is a name that means a certain number like a dozen means 12. 1 mole of chlorine atoms is 6.022 x 10²³ chlorine atoms. The unit conversion is 6.022 x 10²³/mol.

Round to 4.52 x 10²⁴ atoms Cl for the correct number significant figures.
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.