Question

Which of these statements best describes the formula unit for a compound made from Mg and Cl?

Answer 1

Answer:

It is MgCl₂ because the total positive charge on Mg is two

Explanation:

The bond between the atoms that makes up the formula unit of the compound is an ionic bond. This bond involves the transfer of electrons between atoms.

Mg is in the second group on the period on the periodic table. It has two valence electrons and would readily lose it to have a stable atomic configuration like those of noble gases. This leaves magnesium with a net positive charge of 2. Each chlorine atom gains one electron to achieve their own octet.

Answer 2

Answer: The correct statement are:

It is $MgCl_2$ because the total negative charge on Cl is one.

It is $MgCl_2$ because the total positive charge on Mg is two

Explanation:

$Mg^{2+}+2Cl^-\rightarrow MgCl_2$

Magnesium has a 12 atomic number. And will loose 2electrons to attain noble stability.

$[Mg]=1s^22s^22p^23s^2$

$[Mg^{2+}]=1s^22s^22p^23s^0$

Chlorine has a 17 atomic number. And will gain 1 electron to attain noble stability.

$[Cl]=1s^22s^22p^23s^23p^5$

$[Cl^{-}]=1s^22s^22p^23s^23p^6$

So, in 1 molecule of magnesium chloride ,magnesium atom loose its two electrons to two chlorine atoms.