[phann]

Hey so I've just gotten back into school and i've unfortunately forgotten many concepts learned in regular Chemistry. This year i'm taking AP Chemistry and I plan to work as hard as I can.

Anyways here's a question I need help with
Find the number of protons, neutrons, and electrons in an ion of aluminum (Al^3+) with a mass number of 30.

How does the 3+ charge affect the subatomic structure?

Also how do I know what elements have multiple variations? (II),(III) <--- And does this refer to the charge?

Thanks

[Hunter2]

Mass number is sum of protons + sum of neutrons

The atomic number (place in the PSE where the element you find) gives the number of proton and also of electron.

In case of an ion electron less if positive and electron higher if negative as the neutral atom.

Now you can calculate.

[Sweetmormon]

About the (I) (II) (III)
I think those refer to the different oxidation states of a transition metal, for example
Copper can sometimes give 2 electrons to the Oxygen to form Cu₂O thus being called Copper(II) Oxide
.
But Copper(I) will only give one electron to Oxygen making an entirely different compund Copper(I) Oxide.
One is red and one is black
Hope this helps

[Hunter2]

About the (I) (II) (III)
I think those refer to the different oxidation states of a transition metal, for example
Copper can sometimes give 2 electrons to the Oxygen to form Cu₂O thus being called Copper(II) Oxide

Its opposite Cu₂O is copper-I-oxide
and CuO is copper-II-oxide. Oxygen receives 2 electrons.

[deeko]

Also how do I know what elements have multiple variations? (II),(III) <--- And does this refer to the charge?

Thanks

I guess you just need to memories them

[Hunter2]

Correct, some thing has to be learned like others in life. The transitionmetalls have all more oxidation states.

[Vidya]

Hey so I've just gotten back into school and i've unfortunately forgotten many concepts learned in regular Chemistry. This year i'm taking AP Chemistry and I plan to work as hard as I can.

Anyways here's a question I need help with
Find the number of protons, neutrons, and electrons in an ion of aluminum (Al^3+) with a mass number of 30.

How does the 3+ charge affect the subatomic structure?

Also how do I know what elements have multiple variations? (II),(III) <--- And does this refer to the charge?

Thanks

d -block(transition metals) and f- (inner transition metals)block elements are the one which show multiple oxidation numbers.Oxidation number is the  charge on the atom.

[kriggy]

Also how do I know what elements have multiple variations? (II),(III) <--- And does this refer to the charge?

Thanks

I guess you just need to memories them

Indeed but there are some similarities or rules so you can predict or at least partialy if the oxidation state is stable or not. Usualy the most stable oxidation state is the one with full, half -filled or empty d shell. For example, if we compare Mn²⁺ and Fe²⁺, we could easily tell that Mn²⁺ is more stable than Fe²⁺ because the d5 configuration of Mn is more stable than d6 configuration of Fe so Fe gets quite easily oxidized to Fe³⁺ with more stable d5 configuration.
You can aply this reasoning to most of the d elements. Honestly, since you are (I suppose) still at high school, there are better things to learn than all possible oxidation states of all transition metals. Usualy, when you buy a periodic table it has the most common oxidation states noted

[Vidya]

Yes stability of the oxidation numbers and inert pair effect also helps in understanding various oxidation numbers .Like Pb can show +2 and +4 oxidation numbers. This can be understood on the basis of inert pair effect and stability of electronic configurations.