what is a group of atoms having a net electrical charge
A group of atoms with a net electrical charge is called an ion. To understand how ions are formed, let's start with the concept of atoms.
Atoms are the building blocks of matter and consist of positively charged protons, uncharged neutrons, and negatively charged electrons. Normally, the number of protons in an atom equals the number of electrons, resulting in a neutral charge.
However, under certain conditions, atoms can gain or lose electrons, leading to a change in their electrical charge. When an atom gains one or more electrons, it becomes negatively charged and is called an anion. On the other hand, when an atom loses one or more electrons, it becomes positively charged and is called a cation.
The formation of ions can occur in various ways, such as through chemical reactions or the addition/removal of energy. For example, when a sodium atom (Na) loses one electron, it forms a sodium cation (Na+) with a positive charge. Conversely, when a chlorine atom (Cl) gains one electron, it forms a chloride anion (Cl-) with a negative charge.
So, to summarize, a group of atoms having a net electrical charge is known as an ion, which can be either positively charged (cation) or negatively charged (anion) depending on the gain or loss of electrons.