it will lose 3 electrons
3
Iodine tends to gain one electron when it forms an ion.
Aluminum will lose 3 electrons to form Al3+ ion.
An ionic bond.
Sodium loses one electron to form a Na+ ion. Sulfur gains two electrons to form a sulfide ion, S2-.
Se will gain electrons
when it forms an ion it would gain two electrons, becoming negatively charged (2-)
Nitrogen is a unique element. It can loose one, two, three, four, or even five electrons. It can also gain one, two, or three electrons. These are not the only possibilities, however they are the most common.
When Cr3+ forms, the neutral atom (chromium) loses 3 electrons. This happens because the neutral chromium atom has 24 electrons, but when it forms Cr3+, it loses 3 electrons to have a total of 21 electrons.
it should gain 3 electrons
Oxygen will tend to gain 2 electrons to form an ion with a charge of -2. This is because oxygen has 6 valence electrons and is looking to achieve a stable octet configuration like the nearest noble gas, which has 8 valence electrons.
Xenon (Xe) typically forms compounds by gaining two electrons to achieve a stable electron configuration.