What is your opinion about it? Can you think about a reason why they don't form any other type of ions?

I don't know thtz ehy I'm asking...

If you're asking, it probably means that you were first asked that question in class. This also means that you should be able to think up something, at least something, to explain it.

Guessing by your username, you should be 2 years younger than me... that's about the time I got those types of questions too. I'm sure you can find the answer.

Hint: Think about the electronic configurations of the alkali metal atoms, alkali earth metal atoms and noble gas atoms.

Please help me I have 2 submit my h.w on Tuesday

It's against the rules of the forum to do your homework, you have to understand my position too :(

I'll give another hint: Most of the time, atoms will give up or receive electrons to get a complete octet of electrons, in their last electron shell. The energy they gain/lose to achieve this depends on the ionisation energy or electron affinity of the atom. After that, the lattice energy is what will determine whether that final compound is stable or not.

Thank you.. :)