Calculate the number of atoms in 2.5 moles of Si.

Explanation:

When converting from moles to atoms, we must use Avogadro's number. This number tells us there are 6.022 * 10²³ atoms in 1 mole. We can multiply this number by the number of moles.

First, we must set up Avogadro's number as a ratio.

Next, multiply the number of moles by the ratio.

When we multiply, the moles of silicon will cancel.

Since the denominator of the fraction is 1, we can cancel it out too.

The original measurement (2.5 moles) has 2 significant figures (2 and 5). Therefore we must round to 2 sig figs. For this question, 2 sig figs is the tenth place.

The 0 in the hundredth place tells us to leave the 5 in the tenth place.

There are about 1.5 * 10²⁴ atoms of silicon.

the answer is the first option

explanation:

just googled it m8. not that hard

lol

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons