ASVAB Practice Test

When sodium atoms form sodium ions, they lose one electron to become stable. This loss of an electron results in the sodium atom becoming a positively charged ion. Therefore, the correct answer is option A - gain electrons. Option B is incorrect because when sodium atoms lose an electron, they do not gain electrons. Option C is incorrect because sodium atoms do not split into two atoms when forming ions. Option D is incorrect because while sodium ions do become positively charged, this is a result of losing an electron, not gaining one.