What is the correct formula for the compound made by magnesium and nitrogen?

3 Answers
Oct 30, 2015

The correct formula for the Magnesium Nitrogen compound is #Mg_3N_2#.

Explanation:

Magnesium has two valence electrons, and Nitrogen has five valence electrons.

Oct 30, 2015

#Mg_3N_2#, magnesium nitride.

Explanation:

Magnesium is in Group 2, nitrogen is in Group 15; the formula is as you would predict from magnesium ion, #Mg^(2+)#, and nitride anion, #N^(3-)#. This is an ionic solid that hydrolyzes to give ammonia, and magnesium hydroxide, I.e.:

#Mg_3N_2# #+# #6H_2O rarr ##2NH_3# #+# #3Mg(OH)_2#

Oct 30, 2015

Magnesium and nitrogen combine to form magnesium nitride, #"Mg"_3"N"_2"#.

Explanation:

Magnesium nitride is an ionic compound. Magnesium forms ions with a #"2+"# charge, and nitrogen forms nitride ions with a #"3-"# charge. The overall charge of the compound must be zero. Therefore, the numerical value of the positive and negative charge must be #"6"#.

#3["Mg"]^(2+) + 2 ["N"]^(3-)##rarr##"Mg"_3"N"_2"#

#3xx(2+)=6+# and #2xx(3-)=6-#

#(6+)+(6-)=0#

An easy way to determine the formula unit of an ionic compound is called the crisscross method, as demonstrated in the video below.