Answer: C)Anion, it would gain 2 electrons to satisfy the octet rule.
Explanation:
Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom.
The electrons are filled according to Afbau's rule in order of increasing energies and thus the electronic configuration of oxygen with 8 electrons is

The cation is formed by loss of electrons and anions are formed by gain of electrons.
In order to complete its octet and get stable, it gains 2 electrons and thus would form an anion.

Answer:
The right answer is "3 g".
Explanation:
Given:
Initial mass substance,

By using the relation between half lives and amount of substances will be:
⇒ 


Thus, the above is the correct answer.
Answer:
Hailey the answer is D.
Explanation:
if liquid to solid is exothermic then then the other way around would be endorhermic
Answer:
0.4 moles
Explanation:
To convert between moles and grams you need the molar mass of the compound. The molar mass of of CaCO3 is 100.09g/mol. You use that as the unit converter.
40gCaCO3* 1mol CaCO3/100.09gCaCO3 = 0.399640 mol CaCO3
This rounds to 0.4 moles CaCO3
It means <span>a substance formed by chemical union of 2 or more elements or ingredients in definite proportion by weight.</span>