1. One Na+ ion: +1 One CO32- ion: -2
QUESTION:
What is the formula of an ionic compound consisting of Na+ and CO32- ions? A. NaCO3, B. Na2(CO3)2, C. NaCO, D. Na2CO3
The formula of an ionic compound reflects the simplest combination of cations and anions with a total charge of zero.
One Na+ ion: One CO32- ion: -2
One “formula unit” of this compound contains
Two Na+ ions: +1 x 2 = +2 One CO32- ion: -2 x 1 = -2
The formula is Na2CO3.
SCRIPT:
What is the formula of an ionic compound consisting of sodium and carbonate ions? A. NaCO3, B. Na2(CO3)2, C. NaCO, D. Na2CO3
PAUSE
CLICK
The formula of an ionic compound reflects the simplest combination of cations and anions with a total charge of zero.
Since one sodium ion has a charge of +1
and one carbonate ion has a charge of –2,…
CLICK The simplest combination of ions with a total charge of zero consists of
Two sodium ions…. +1 per sodium ion, times 2, equals +2
And one carbonate ion,…. –2 per carbonate ion, times 1, equals –2.
This combination,… two cations and one anion,… gives us a total charge of zero….. +2 plus –2 equals zero.
The corrrect answer is choice D.

2. Video ID: © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Narrator: Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08