Asked by Chris

Criticize the following statements.

1. In an ionic compound, the number of cations is always equal to the number of anions. [Is it ok to say 'not always'?]

2. The molecular formula for strontium bromide is SrBr(sub 2) [what's wrong wih this?]

3. The mass number is always equal to the atomic number. [never?]

4. For any ion, the number of electrons is always more than the number of protons. [is always equal to]


Criticize the following statements.

1. In an ionic compound, the number of cations is always equal to the number of anions. [Is it ok to say 'not always'?]
<b>No, the number of cations is not always equal to the number of anions. Sometimes, yes; always, no.</b>

2. The molecular formula for strontium bromide is SrBr(sub 2) [what's wrong wih this?]
<b>Initially I didn't know what was wrong since the formula IS SrBr2; however, after reflecting for some time, I believe that the clue here is that SrBr2 is an ionic compound. Therefore, the ions are in a three dimensional array, or network. Although the RATIO is 1:2, in reality, the molecular formula is Sr(sub x)Br(sub 2x) and we don't know x because that depends upon how large a crystal of SrBr2 we observe. Same thing with NaCl. We write the simplest formula as NaCl but it actually is NaxClx. BTW, I found a reference in my copy of Advanced Inorganic Chemistry (Cotton & Wilkiinson), Fifth edition, that the halides of Sr and others, although existing as ionic compounds, COULD be vaporized as molecular compounds.</b>

3. The mass number is always equal to the atomic number. [never?]
<b>Never is correct.</b>

4. For any ion, the number of electrons is always more than the number of protons. [is always equal to]
<b>No. Electrons are in excess for negative ions, protons are in excess for positive ions. The number of electrons is equal to the number of protons in a neutral element.<b>

how inteligent you are chris

Answers

Answered by Ron
Thanks!

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