How do i figure out the # of electrons which need to be lost...?

Question

to acquire a noble gas electron arrangement?

Lithium for example. It has 3 protons.

Why does it need to lost ANything?

So confused. Got this problem from a textbook.

All help is greatly apreciated <333

Answer 1

Li has 3 protons and therefore 3 electron. Therefore its electron configuration is 1s2 2s1

The electron configuration of He (a noble gas) is 1s2

1s2 2s1 - 1 electron = 1s2

Answer 2

The number of protons is the same as the number of electrons, which is the important thing. An element needs to gain or lose a certain number of electrons in order to achieve the configuration of a noble gas. Usually, that means they need to get up to (0), 2, or 8 electrons by losing and gaining valence electrons. Lithium for example, needs to lose 1 electron to have 2, which would be the noble gas Helium. Hope that helped. Take a look at this photo to make things easier (colours show how many electrons needs to be gained or lost) http://en.wikipedia.org/wiki/Valence_(ch...