The lithium atom has no charge because the number of protons in the nucleus is equal to the number of electrons orbiting the nucleus. Protons have a positive charge, while electrons have a negative charge. When the number of protons and electrons are equal, the overall charge of the atom is neutral.

In the case of lithium, there are three protons in the nucleus and three electrons orbiting the nucleus. This means that the lithium atom has a net charge of zero.