You are given a sentence and your task is to generate another sentence that supports the given input.

1) Each sperm has a head (nucleus and acrosome), midpiece (mitochondria), and tail (microtubules).
The head of the sperm contains the nucleus.

A lithium atom has a still heavier nucleus and three electrons.
Lithium has three electrons.

An atom that gains electrons would be a negative ion.

Atoms that have gained electrons and become negatively charged are called negative ions.