Question

How can two atoms of the same chemical element be different?

A.
They may be different isotopes of the element. Each isotope of the same element has a different number of neutrons.

B.
They may be different allotropes of the element. Each allotrope of the same element has a different number of neutrons.

C.
They may be different isotopes of the element. Each isotope of the same element has a different number of electrons.

D.
They may be different allotropes of the element. Each allotrope of the same element has a different number of electrons.

Answer 1

You should be able to look that up on the internet very easily...

take a look here:
http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/nucnot.html

Answer 2

I went with A. I'm I right ? @furnessj

Answer 3

That is correct :)

Answer 4

Thank you :)

Answer 5

Can you help me with one last question ? @furnessj
I remember this being a little tricky.
I think it's D.

Answer 6

It is D, you should easily be able to explain why..

first concentrate only on horizontal forces, which one 'wins' the battle? [which is the bigger force]
now look at the vertical forces only, which direction 'wins'?

what you have left are just two forces, in two directions. These can be added using the tip - to - tail method:

Answer 7

Lol, ok. I liked the way you explained it :)

Answer 8

Thanks - I should have said that of course what you are doing is finding the overall effect of 4 forces by a process of summing each force in the x- and y-direction, then finding the overall net (resultant) force. You can also work out the exact direction (angle using some simple trigonometry).

Answer 9

Okay, thanks for your help.