h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

This comes from a True False quiz:

Atoms have the same number of protons as electrons. T or F.

"Correct" answer is False, according to the quiz.

I'm not sure - I thought Atoms were neutral, if they are not they are called ions....

Answers.com agrees with the quiz, Wikipedia kind of agrees - saying a neutral atom has the same no.... but "[a] charged atom is known as an ion"...

So is an ion and atom?

An atom is "normally" neutrally "charged", meaning it has the same number of electrons as protons in its nucleus. It can become negatively charged by gaining an additional electron (forming an anion) or it can become positively charged by losing an electron (forming a cation). Hence the correct answer is indeed false.

ps In "chemistry" atoms are "continually" losing and gaining electrons (undergoing various chemical reactions), but we don't say that the atoms are being "destroyed and created", we say that electrons are moving from one atom to another (they are also shared between atoms).

In any chemical reaction there is a "conservation of atoms", something one learns at an elementary level when attempting to "balance" a chemical "equation".

I'd say they are all talking nonsense and I would agree with you Argon0

And ions are any charged species (from protons and bigger at least, I'm not sure you'd call an electron an ion).

So you can have molecular ions as well as atomic ions if you see what I mean.

>Atoms have the same number of protons as electrons. T or F.<

It's not really a very good true of false question though. Full of ambiguities.

As wikipedia says a NEUTRAL atom will have equal numbers of both - a charged atom (ion) will not.

So it does depend...


If I was forced to stake my life on it, I'd agree with you.

Thinking about it as single particles, then indeed Argon0 is correct. However, there are considerable grey areas around covalent bonding, not to mention low-temperature chemistry. In both of these, it's not always appropriate to assign an electron to a 'parent' nucleus.

B

Which is why it is an extremely poor question to give a T or F answer to.

True, but if it's a neutral molecule - the number of electrons still equal the number of electrons and protons overall.

I agree that it was a "rubbish" true or false question.

"True, but if it's a neutral molecule - the number of electrons still equal the number of electrons and protons overall."

Of course if it was a neutral molecule, you definitely WOULDN'T refer to it as an atom.

B

Thanks guys, I agree it is a rubbish T or F question, but there do seem to be a lot of them about...

Yes Mu B, but a molecule is composed of atoms back