The elements in group 1 of the periodic table are known as alkali metals. When these elements react with other substances, they tend to lose one electron from their outermost shell, resulting in the formation of positively charged ions known as cations. These cations have a charge of +1.

For example, when sodium (Na) reacts, it loses one electron to form the sodium ion (Na+). Similarly, potassium (K) loses one electron to form the potassium ion (K+).

The general chemical formula for the ions formed by group 1 elements is "M+", where "M" represents the symbol of the element.