Answer:
Na has the most similar configuration.
Explanation:
Na electron configuration: 1s²2s²2p⁶3s¹ or [Ne] 3s₁
Mg electron configuration: 1s²2s²2p⁶3s² or [Ne] 3s²
Be electron configuration: 1s²2s² or [He] 2s²
This is because Na and Mg are right next to each other in the same period (horizontal).
The answer is A (The ability to react with oxygen)
Explanation:
Ion-dipole interactions are defined as the interactions that occur when an ion interacts with the dipole of a molecule (polar molecule).
For example, 
, 
, 
, NaCl etc are all the molecules that will show ion-dipole interactions.
Dipole-dipole interactions are defined as the interactions that occur when partial positive charge on an atom is attracted by partial negative charge on another atom.
When a polar molecules produces a dipole on a non-polar molecule through distribution of electrons then it is known as dipole-induced forces.
For example, 
, 
etc are the molecules which show dipole-dipole interactions.
None of these; the most electronegative element is fluorine because an atom of fluorine needs an additional electron to join it's outer membrane, so the atom can achieve stability.
a flourine atom on its own is always a negative ion.
