1) What is the chemical formula for the compound formed between thallium(iii) and bromine?

2) What is the chemical formula for the compound formed between thallium(iii) and sulfur?

HINT!: each compound wil be neutral. What is the charge of the thallium(iii) ion? What is the charge of the most common ion formed by bromine and sulfur?

2 answers

The easy way to do these is to write (ignore the dots--I must do that for spacing) the symbols.

......Tl....Br
Then write above the symbols the valence. For Tl that is +3 (the III tells you that and for Br it is -1.
......+3..-1
...... Tl.Br
Now make a big X through that dot in the middle between Tl and Br. The top left of the X is the +3, bring it down to the bottom right on Br. The 1 (ignore the - sign) at the top right for over Br; bring that down to the bottom left of the X So te formula is
TlBr3.

Do the same for Tl and S. Use +3 for Tl and -2 for S.
What is the chemical formula for the compound formed between chromium(VI) and bromine?