Chemistry Tutorial 2.02d: Basics Of Formula Writing

This video describes how simple binary ionic formulas are written given ion charges.

Category:

Education

Tags:

• chemistry
• rosengarten
• chemical
• formulas
• formula
• writing

[bonsalakot]

the most easiest way is to use the criss-cross method..question isn't that Al(O2)3 is this right? Al(O2)3 and Mg(N3)2?

[MarkRosengarten]

@bonsalakot No. Al2O3 and Mg3N2. O and N are diatomic only when by themselves. When in a compound, use the charges listed.

[TheFrimond]

why is Al2O3 named as aluminum oxide not aluminum trioxide?

[MarkRosengarten]

@TheFrimond A few reasons:

1) Al2O3 is ionic. Ionic compounds do not use the prefix system. Granted, Al2O3 has a pretty high covalent character compared to most ionic compounds but the rule still applies.

2) There is only one possible way that aluminum and oxide can form a compound. If there more than one way, as with iron and oxide, then a Roman numeral would be used to indicate the metal ion's charge. Fe can be +2 or +3, so...

Continued on the next reply

[MarkRosengarten]

@TheFrimond FeO (where Fe has a +2 charge) is called iron (II) oxide and Fe2O3 (where Fe has a +3 charge) is called iron (III) oxide. Al can only be +3, so AlCl3 is aluminum chloride, Al(NO3)3 is aluminum nitrate and Al2O3 is aluminum oxide.

[ron13rojo]

because of you, sir.. you made my grades increase!! thank you very much. :)

[MarkRosengarten]

@ron13rojo You made your own grades increase! You made the conscious effort to find help, and you found it! While I am glad that I could be of service to you, YOU looked, YOU watched, YOU understood and YOU improved! :) Congratulations!

[deaneden79]

THANK YOU THANK YOU THANK YOU!!! Feels like I'm trying to learn Japanese or something but your explanations are so logical. Thanks again!! Understanding the basics of organic chemistry feels so difficult.

[Boxrag]

WHY COULDN' MY CHEMISRY TEACHER EXPLAIN THINGS AS CONCISE. EVERYTHING MAKES SENSE.

[madformaddysmaddies]

thank you very much sir!!! I am in 4th grade and am interested in chemistry, and you made formula writing very clear to me, and increased my interest in the subject.Thanks to you, I can manage to get and secure great grades!!Thanks! XDXDXDXD

[trinxie000]

very helpful.. thanks :D

[bonsalakot]

@MarkRosengarten oh i see thanks.

[bonsalakot]

@bonsalakot Uhmm isn't that when a polyatomic ion is taken for more than once, you need to right a parenthesis after that write the frequency occurrence as a subscript. is this right? you know when you read the formula Aluminum quantity oxygen 2 quantity three?

[rrrlightsauri]

thanks2x .......u save my life.. i was able to understand this lesson... hehehehehe my teacher assign me to report this topic.... thank you!!!!!!!!!!!!!!!