Explanation:
Atomic number of magnesium is 12 and its electronic distribution is 2, 8, 2. To attain noble gas configuration it is necessary for the magnesium atom to lose two valence electrons and therefore, it forms 
ions.
On the other hand, atomic number of oxygen atom is 8 and its electronic distribution is 2, 6. To attain noble gas configuration it needs to gain two electrons. And, on gaining the electrons it forms 
ions.
Hence, when both magnesium and oxygen ions chemically combine with each other then it forms the compound magnesium oxide (
).
This is because magnesium transfer its two valence electrons to the oxygen atom and due to the formation of opposite charges on these atoms they get attracted towards each other.
-<u><em>Oxygen</em></u>
According to Google these are the percentages of the <em>Earths Atmosphere</em>
<em>1</em> 78% - Nitrogen
<u>2</u> 21% - Oxygen
<em>3</em> 0.9% - Argon
<em>4 </em>0.3 - Carbon Dioxide with very small percentage of other elements.
Answer:
Hi there!
The correct answer to this question is: electrons enter orbitals of lowest energy first.
Answer no 1)
The correct option is A) He did not try to learn it. It was natural.
As Sergei did not put any effort in learning the art of tongue rolling, hence we can assume that this characteristic was found to be naturally present in Sergei. This hence shows that Sergei has acquired the characteristic of tongue rolling through inheritance.
Answer No 2)
We can learn whether other persons in the class have the characteristic of tongue rolling or not by observing them. In the students who can roll their tongue we can conduct a survey asking them whether they tried to learn the trait or did not put any effort to learn tongue rolling. The students who learned the skill by practicing might have acquired the characteristic from learning.
Answer No 3)
We can survey the class for features like eye color, hair color, height, weight. We can ask certain questions in our survey like whether the characteristic can be seen in either the mother, father or other siblings.
IT IS NOT POSSIBLE TO RETRIEVE A BOTTLE OF SULFATE BECAUSE SULFATE DOES NOT EXIST AS A DISTINCT CHEMICAL COMPOUND.
Sulphate is a polyatomic ion. A polyatomic ions refers to group of atoms that carry charges. Sulfate carries a charge of +2. Sulfate is a very reactive ion, thus, it can not be found existing on its own, it is always found in combination with other elements, such elements include H2SO4 and CaSO4.
