How does atom become an ion?
An atom becomes an ion when it loses or gains an electron. An atom is electrically neutral. The protons and electrons are equal and balance each other. An ion is either positive or negative, depending on whether it gains or loses an electron. Thus the number of electrons will be either greater or less than the number of positively charged protons.
It becomes a positively charged ion, called a cation. A neutral atom has the same number of protons and electrons. Since protons are positively charged and electrons are negatively charged, if an atom loses an electron, it will then have one more proton than electrons, which will make it an ion with a charge of 1+.
An atom has the same number of protons and electrons. Thus, the charge is neutral. An ion is a charged atom, which means it has a charge of some type (positive or negative). If a lithium atom (3 protons and 3 electrons) gains two electrons, it will become an ion with a charge of 2-. If it loses 3 electrons, it will become an ion with a charge of 3+