Answer:
12, 28, 16
Explanation:
If we are trying to find mass, neutrons are our guy. 28 "mass points" means 28 neutrons. Each neutron is one point
We know there are 12 protons and electrons if we look at a table of elements, the number in the top-left is always the number of protons and we can subtract mass from the protons to get our electrons
Number of atoms : 1.26 x 10²³
<h3>Further explanation </h3>
The mole is the number of particles(molecules, atoms, ions) contained in a substance
1 mol = 6.02.10²³ particles
Can be formulated
N=n x No
N = number of particles
n = mol
No = Avogadro's = 6.02.10²³
0.21 moles of Al, so n = 0.21
Number of atoms :
To convert the formula unit to mass, we need to divide the given formula units by Avogadro's number, 6.022 x 10^23 and we get the mole of beryllium nitrate. To convert to mass, we need to multiply the number of moles with the molecular formula of the compound which is 133.022 g/mol.The answer is 0.006185 g or 6.185 mg.
<span>it tells you the sequence in which events occurred, not how long ago they occurred.</span>
