20 Ca :
1s², 2s², 2p⁶, 3s², 3p⁶, 4s²<span>
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Answer D
hope this helps!

Actually Welcome to the Concept of the Ionic bonds.
Since Sodium (Na) is a cation and Chlorine (Cl) is a Anion, they both form a Ionic bond called as NaCl (common salt)
So answer is, Na and Cl
3 cubic centimeters, Volume= density/ mass
<span> under extreme heat or pressure
crystallize from magma
precipitate from a solution reaction of hot mixture with water and a dissolved substance</span>