The Calcium ion is an Alkaline earth metal and wants to give up the 2 s orbital elections and become a +2 cation.
Oxygen has six valence electrons and is looking to gain two electrons to complete the octet (8) electron count in the valence shell making it a -2 anion.
When the charges of the Calcium +2 and the Oxygen -2 are equal and opposite, the ions for an electrical attraction. (Remember Paula Abdul told us "Opposites Attract")
This one to one ratio of charges makes the formula CaO
Unsaturated hydrocarbons are those in which each carbon atom is attached to as many hydrogen atoms as it possibly can. There can be no double bonds or non-hydrogen functional groups, since these detract from the maximum possible number of hydrogens that each carbon can be attached to (in the case of double bonds, two carbons are bonded to each other when they could alternately be bonded to one more hydrogen each).
All of the alkanes (including the cycloalkanes) are saturated hydrocarbons. Substituted alkanes, alkenes, alkynes, and their cyclic counterparts are all unsaturated.
Answer:

Or
[He] 2s2 2p2
Explanation:
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Incomplete combustion (where an element or compound reacts with oxygen to produce carbon monoxide and water) as a result of too little oxygen being available such that complete combustion(in which the first product is carbon dioxide instead) is not possible.
Answer:
D)
Explanation:
I just answered the question and got it right.