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Chemistry / Re: How to calculate the maximum charge of an atom or a molecule?
« on: 11/08/2018 01:56:31 »One must use a periodic table and some rules of thumb (some elements can have multiple oxidation states/charges).Could you tell me please when Cl, Br and I can sometimes lose 1 electron?
In general, elements in the left 2/3 of the periodic table will lose electrons and form positively charged ions (formal oxidation states), while in the right 1/3 they will gain electrons and form negatively charged ions (formal oxidation states). The number of electrons lost or gained can be determined based on how far they are from the edges of the periodic table.
The first column (H, Li, Na, K, etc.) will lose 1 electron.
The second column (Be, Mg, Ca, etc.) will lose 2 electrons.
The transition metals are tricky, and will not be discussed here, but it is typically a safe bet that they lose electrons.
The next column (B, Al, Ga, etc.) will lose 3 electrons.
The next column (C, Si, Ge, etc.) will lose or gain 4 electrons.
The next column (N, P, As, etc.) will gain 3 electrons.
The next column (O, S, Se, etc.) will gain 2 electrons.
The next column (F, Cl, Br, etc.) will gain 1 electron.
The last column (He, Ne, Ar, etc. won't gain or lose any electrons.
The f block (those two rows often shown separated at the bottom) is also tricky, but it's typically a safe bet that they lose 3 electrons.
Occasionally H gains 1 electron (some people even place it in the second to last column, over F on the periodic table)
Also, Cl, Br and I can sometimes lose 1 electron.