Decoding chemical formulae

Q1: Which elements are present in CaCO3?

Incorrect - new elements begin with a capital letter, so CaCO3 contains Ca, C and O.
Correct - well done!
Incorrect - new elements begin with a capital letter, so CaCO3 contains Ca, C and O.


Decoding chemical formulae

Q2: Which elements are present in AlF3?

Correct - well done!
Incorrect - new elements begin with a capital letter, so AlF3contains Al and F.
Incorrect - new elements begin with a capital letter, so AlF3contains Al and F.


Decoding Chemical Formulae

Q3: Which statement below best describes CH4?

Incorrect - remember if there's no number next to an elements symbol you have to imagine there's a number 1.
Incorrect - remember if there's no number next to an elements symbol you have to imagine there's a number 1.


Decoding chemical formulae

Q4: Which statement below best describes HNO3?

Afraid not - remember that if there's no number next to an element you have to pretend that there is a one. So there's 1 nitrogen not 3.
Incorrect - remember if there's no number next to an element's symbol you have to pretend that there's a one there. So in this care there is one hydrogen and 1 nitrogen.


Decoding Chemical Formulae

Q5: Which of these best describes Mg(NO3)2?

Incorrect - the brackets muliply everything that's inside - so the nitrogen must be doubled as well.
Incorrect - there's one nitrogen inside the brackets as there is no number next to it. The brackets then multiply it by 2 to give 2 nitrogen atoms.
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