chemistry - electrons?

Question

im so confused.. please help..

Write the name and symbol of the ion formed when
a. a sulfer atom gains 2 electrons
b. an alluminium atom loses 3 electrons

how do u do that?

for a) would it be something like S2+?
and b) Al3-? or just Al because its Al3+ in the periodic table?


How many electrons are lost or gained in forming each ion?
a) Ba2+ b) As3- c)Cu3+

a) 2 gained? b) 3 lost? c) 3 gained?

Answer 1

S2- (b) Al3+ S+2- = S2-
Al = Al +3-
(a) two elctrons are lost.
(b)three electrons are gained
(c) three electrons are lost.

Answer 2

Hi, the correct answers are the same in number but the resultant charge is the reverse of what you think.
Remember that an electron always carries one single negative charge, so it can be represented as e-. Now, a sulfer atom (symbol S), like all atoms in the periodic table is by definition always neutral. This is because it contains an equal number of negative electrons and positive protons balancing each other out in the atom. So when a sulfer atom gains two electrons, you are adding two e-, so S must become negatively charged.
So:
S plus 2e- ----> S2-

Simple, huh?

For your aluminium (symbol Al) question, when you lose electrons from an atom, it follows that you are losing negative charge, and the result is that there is now one less electron for each postive proton in the atom, so the atom becomes positively charged, because the original balance is lost and there is now an excess of positively charged protons in the nucleus.
So:
Al minus 3e- ----> Al3+

So exactly the same applies for your other questions:
Ba has lost two electrons, As has gained three electrons and Cu has lost three electrons.
I hope that helps,
Regards,
Julian.

Answer 3

yes i think you a confussed
but relax
it is easy
remember the following things:
(i)when electron is given out it attains positive

(+) charge and it is denoted by a positive (+)

sign on it

(ii)when electron is gained it attains a negative

(-) charge and it is denoted by a negative sign

on it

these hints will solve your problems

Answer 4

+ means electron lost !
- means electron gained (since electron is "negetive" charged)