An element or ion that has lost two electrons must have a net charge of 2+, because it has two more protons than electrons, therefore the answer is Mg2+
H2 is colorless and odorless
NO2 is brown, pungent, and toxic
Answer:
The answer should be I and III
Abiotic
is the answer for you
Answer:
Approximately 
.
Explanation:
Lookup Avogadro's Number: 
(three significant figures.)
Lookup the relative atomic mass of 
, 
, and 
on a modern periodic table:
(For example, the relative atomic mass of is 
means that the mass of one mole of 
atoms would be approximately 
grams on average.)
The question counted the number of 
molecules without using any unit. Avogadro's Number 
helps convert the unit of that count to moles.
Each mole of molecules includes exactly 
of these 
molecules.
molecules would correspond to 
of such molecules.
(Keep more significant figures than required during intermediary steps.)
The formula mass of gives the mass of each mole of 
molecules. The value of the formula mass could be calculated using the relative atomic mass of each element:
.
Calculate the mass of approximately 
of :
.
(Rounded to three significant figures.)
.
.