Final answer:
When an Li atom becomes an Li+ ion, it loses one electron and achieves a noble gas configuration. The Li+ ion has a net charge of +1.
Step-by-step explanation:
When an Li atom becomes an Li+ ion, it loses one electron. This electron transfer occurs because lithium has one valence electron in its outermost shell. By losing this electron, lithium achieves a noble gas configuration, which is a more stable electron arrangement. The resulting Li+ ion has a net charge of +1 due to the loss of one electron.